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authorLinus Torvalds <torvalds@linux-foundation.org>2021-11-01 13:24:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-01 13:24:43 -0700
commit43aa0a195f06101bcb5d8d711bba0dd24b33a1a0 (patch)
tree0236661db875f519cc80e11fde210fdfc9b2be76 /arch/x86
parent595b28fb0c8949463d8ec1e485f36d17c870ddb2 (diff)
parent87c87ecd00c54ecd677798cb49ef27329e0fab41 (diff)
downloadlinux-43aa0a195f06101bcb5d8d711bba0dd24b33a1a0.tar.bz2
Merge tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool updates from Thomas Gleixner: - Improve retpoline code patching by separating it from alternatives which reduces memory footprint and allows to do better optimizations in the actual runtime patching. - Add proper retpoline support for x86/BPF - Address noinstr warnings in x86/kvm, lockdep and paravirtualization code - Add support to handle pv_opsindirect calls in the noinstr analysis - Classify symbols upfront and cache the result to avoid redundant str*cmp() invocations. - Add a CFI hash to reduce memory consumption which also reduces runtime on a allyesconfig by ~50% - Adjust XEN code to make objtool handling more robust and as a side effect to prevent text fragmentation due to placement of the hypercall page. * tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) bpf,x86: Respect X86_FEATURE_RETPOLINE* bpf,x86: Simplify computing label offsets x86,bugs: Unconditionally allow spectre_v2=retpoline,amd x86/alternative: Add debug prints to apply_retpolines() x86/alternative: Try inline spectre_v2=retpoline,amd x86/alternative: Handle Jcc __x86_indirect_thunk_\reg x86/alternative: Implement .retpoline_sites support x86/retpoline: Create a retpoline thunk array x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h x86/asm: Fixup odd GEN-for-each-reg.h usage x86/asm: Fix register order x86/retpoline: Remove unused replacement symbols objtool,x86: Replace alternatives with .retpoline_sites objtool: Shrink struct instruction objtool: Explicitly avoid self modifying code in .altinstr_replacement objtool: Classify symbols objtool: Support pv_opsindirect calls for noinstr x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays x86/xen: Mark xen_force_evtchn_callback() noinstr x86/xen: Make irq_disable() noinstr ...
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/GEN-for-each-reg.h14
-rw-r--r--arch/x86/include/asm/alternative.h1
-rw-r--r--arch/x86/include/asm/asm-prototypes.h18
-rw-r--r--arch/x86/include/asm/nospec-branch.h72
-rw-r--r--arch/x86/include/asm/paravirt.h31
-rw-r--r--arch/x86/include/asm/ptrace.h2
-rw-r--r--arch/x86/include/asm/xen/hypercall.h6
-rw-r--r--arch/x86/kernel/alternative.c191
-rw-r--r--arch/x86/kernel/cpu/bugs.c7
-rw-r--r--arch/x86/kernel/irqflags.S2
-rw-r--r--arch/x86/kernel/module.c9
-rw-r--r--arch/x86/kernel/paravirt.c45
-rw-r--r--arch/x86/kernel/sev-shared.c2
-rw-r--r--arch/x86/kernel/vmlinux.lds.S14
-rw-r--r--arch/x86/kvm/svm/svm.h8
-rw-r--r--arch/x86/kvm/svm/svm_ops.h4
-rw-r--r--arch/x86/kvm/vmx/evmcs.h4
-rw-r--r--arch/x86/lib/retpoline.S56
-rw-r--r--arch/x86/net/bpf_jit_comp.c160
-rw-r--r--arch/x86/net/bpf_jit_comp32.c22
-rw-r--r--arch/x86/xen/enlighten_pv.c70
-rw-r--r--arch/x86/xen/irq.c31
-rw-r--r--arch/x86/xen/mmu_pv.c93
-rw-r--r--arch/x86/xen/xen-asm.S79
-rw-r--r--arch/x86/xen/xen-head.S34
25 files changed, 546 insertions, 429 deletions
diff --git a/arch/x86/include/asm/GEN-for-each-reg.h b/arch/x86/include/asm/GEN-for-each-reg.h
index 1b07fb102c4e..07949102a08d 100644
--- a/arch/x86/include/asm/GEN-for-each-reg.h
+++ b/arch/x86/include/asm/GEN-for-each-reg.h
@@ -1,11 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * These are in machine order; things rely on that.
+ */
#ifdef CONFIG_64BIT
GEN(rax)
-GEN(rbx)
GEN(rcx)
GEN(rdx)
+GEN(rbx)
+GEN(rsp)
+GEN(rbp)
GEN(rsi)
GEN(rdi)
-GEN(rbp)
GEN(r8)
GEN(r9)
GEN(r10)
@@ -16,10 +21,11 @@ GEN(r14)
GEN(r15)
#else
GEN(eax)
-GEN(ebx)
GEN(ecx)
GEN(edx)
+GEN(ebx)
+GEN(esp)
+GEN(ebp)
GEN(esi)
GEN(edi)
-GEN(ebp)
#endif
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index a3c2315aca12..58eee6402832 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -75,6 +75,7 @@ extern int alternatives_patched;
extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
+extern void apply_retpolines(s32 *start, s32 *end);
struct module;
diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h
index 4cb726c71ed8..8f80de627c60 100644
--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -17,21 +17,3 @@
extern void cmpxchg8b_emu(void);
#endif
-#ifdef CONFIG_RETPOLINE
-
-#undef GEN
-#define GEN(reg) \
- extern asmlinkage void __x86_indirect_thunk_ ## reg (void);
-#include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) \
- extern asmlinkage void __x86_indirect_alt_call_ ## reg (void);
-#include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) \
- extern asmlinkage void __x86_indirect_alt_jmp_ ## reg (void);
-#include <asm/GEN-for-each-reg.h>
-
-#endif /* CONFIG_RETPOLINE */
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index ec2d5c8c6694..cc74dc584836 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -5,12 +5,15 @@
#include <linux/static_key.h>
#include <linux/objtool.h>
+#include <linux/linkage.h>
#include <asm/alternative.h>
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
#include <asm/unwind_hints.h>
+#define RETPOLINE_THUNK_SIZE 32
+
/*
* Fill the CPU return stack buffer.
*
@@ -118,6 +121,16 @@
".popsection\n\t"
#ifdef CONFIG_RETPOLINE
+
+typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
+
+#define GEN(reg) \
+ extern retpoline_thunk_t __x86_indirect_thunk_ ## reg;
+#include <asm/GEN-for-each-reg.h>
+#undef GEN
+
+extern retpoline_thunk_t __x86_indirect_thunk_array[];
+
#ifdef CONFIG_X86_64
/*
@@ -303,63 +316,4 @@ static inline void mds_idle_clear_cpu_buffers(void)
#endif /* __ASSEMBLY__ */
-/*
- * Below is used in the eBPF JIT compiler and emits the byte sequence
- * for the following assembly:
- *
- * With retpolines configured:
- *
- * callq do_rop
- * spec_trap:
- * pause
- * lfence
- * jmp spec_trap
- * do_rop:
- * mov %rcx,(%rsp) for x86_64
- * mov %edx,(%esp) for x86_32
- * retq
- *
- * Without retpolines configured:
- *
- * jmp *%rcx for x86_64
- * jmp *%edx for x86_32
- */
-#ifdef CONFIG_RETPOLINE
-# ifdef CONFIG_X86_64
-# define RETPOLINE_RCX_BPF_JIT_SIZE 17
-# define RETPOLINE_RCX_BPF_JIT() \
-do { \
- EMIT1_off32(0xE8, 7); /* callq do_rop */ \
- /* spec_trap: */ \
- EMIT2(0xF3, 0x90); /* pause */ \
- EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
- EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
- /* do_rop: */ \
- EMIT4(0x48, 0x89, 0x0C, 0x24); /* mov %rcx,(%rsp) */ \
- EMIT1(0xC3); /* retq */ \
-} while (0)
-# else /* !CONFIG_X86_64 */
-# define RETPOLINE_EDX_BPF_JIT() \
-do { \
- EMIT1_off32(0xE8, 7); /* call do_rop */ \
- /* spec_trap: */ \
- EMIT2(0xF3, 0x90); /* pause */ \
- EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
- EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
- /* do_rop: */ \
- EMIT3(0x89, 0x14, 0x24); /* mov %edx,(%esp) */ \
- EMIT1(0xC3); /* ret */ \
-} while (0)
-# endif
-#else /* !CONFIG_RETPOLINE */
-# ifdef CONFIG_X86_64
-# define RETPOLINE_RCX_BPF_JIT_SIZE 2
-# define RETPOLINE_RCX_BPF_JIT() \
- EMIT2(0xFF, 0xE1); /* jmp *%rcx */
-# else /* !CONFIG_X86_64 */
-# define RETPOLINE_EDX_BPF_JIT() \
- EMIT2(0xFF, 0xE2) /* jmp *%edx */
-# endif
-#endif
-
#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index da3a1ac82be5..cebec95a7124 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -52,11 +52,11 @@ void __init paravirt_set_cap(void);
/* The paravirtualized I/O functions */
static inline void slow_down_io(void)
{
- pv_ops.cpu.io_delay();
+ PVOP_VCALL0(cpu.io_delay);
#ifdef REALLY_SLOW_IO
- pv_ops.cpu.io_delay();
- pv_ops.cpu.io_delay();
- pv_ops.cpu.io_delay();
+ PVOP_VCALL0(cpu.io_delay);
+ PVOP_VCALL0(cpu.io_delay);
+ PVOP_VCALL0(cpu.io_delay);
#endif
}
@@ -113,12 +113,12 @@ static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
/*
* These special macros can be used to get or set a debugging register
*/
-static inline unsigned long paravirt_get_debugreg(int reg)
+static __always_inline unsigned long paravirt_get_debugreg(int reg)
{
return PVOP_CALL1(unsigned long, cpu.get_debugreg, reg);
}
#define get_debugreg(var, reg) var = paravirt_get_debugreg(reg)
-static inline void set_debugreg(unsigned long val, int reg)
+static __always_inline void set_debugreg(unsigned long val, int reg)
{
PVOP_VCALL2(cpu.set_debugreg, reg, val);
}
@@ -133,14 +133,14 @@ static inline void write_cr0(unsigned long x)
PVOP_VCALL1(cpu.write_cr0, x);
}
-static inline unsigned long read_cr2(void)
+static __always_inline unsigned long read_cr2(void)
{
return PVOP_ALT_CALLEE0(unsigned long, mmu.read_cr2,
"mov %%cr2, %%rax;",
ALT_NOT(X86_FEATURE_XENPV));
}
-static inline void write_cr2(unsigned long x)
+static __always_inline void write_cr2(unsigned long x)
{
PVOP_VCALL1(mmu.write_cr2, x);
}
@@ -653,10 +653,10 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
* functions.
*/
#define PV_THUNK_NAME(func) "__raw_callee_save_" #func
-#define PV_CALLEE_SAVE_REGS_THUNK(func) \
+#define __PV_CALLEE_SAVE_REGS_THUNK(func, section) \
extern typeof(func) __raw_callee_save_##func; \
\
- asm(".pushsection .text;" \
+ asm(".pushsection " section ", \"ax\";" \
".globl " PV_THUNK_NAME(func) ";" \
".type " PV_THUNK_NAME(func) ", @function;" \
PV_THUNK_NAME(func) ":" \
@@ -669,6 +669,9 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
".size " PV_THUNK_NAME(func) ", .-" PV_THUNK_NAME(func) ";" \
".popsection")
+#define PV_CALLEE_SAVE_REGS_THUNK(func) \
+ __PV_CALLEE_SAVE_REGS_THUNK(func, ".text")
+
/* Get a reference to a callee-save function */
#define PV_CALLEE_SAVE(func) \
((struct paravirt_callee_save) { __raw_callee_save_##func })
@@ -678,23 +681,23 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
((struct paravirt_callee_save) { func })
#ifdef CONFIG_PARAVIRT_XXL
-static inline notrace unsigned long arch_local_save_flags(void)
+static __always_inline unsigned long arch_local_save_flags(void)
{
return PVOP_ALT_CALLEE0(unsigned long, irq.save_fl, "pushf; pop %%rax;",
ALT_NOT(X86_FEATURE_XENPV));
}
-static inline notrace void arch_local_irq_disable(void)
+static __always_inline void arch_local_irq_disable(void)
{
PVOP_ALT_VCALLEE0(irq.irq_disable, "cli;", ALT_NOT(X86_FEATURE_XENPV));
}
-static inline notrace void arch_local_irq_enable(void)
+static __always_inline void arch_local_irq_enable(void)
{
PVOP_ALT_VCALLEE0(irq.irq_enable, "sti;", ALT_NOT(X86_FEATURE_XENPV));
}
-static inline notrace unsigned long arch_local_irq_save(void)
+static __always_inline unsigned long arch_local_irq_save(void)
{
unsigned long f;
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index b94f615600d5..703663175a5a 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -181,7 +181,7 @@ static inline bool any_64bit_mode(struct pt_regs *regs)
#define current_user_stack_pointer() current_pt_regs()->sp
#define compat_user_stack_pointer() current_pt_regs()->sp
-static inline bool ip_within_syscall_gap(struct pt_regs *regs)
+static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs)
{
bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack);
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index 454b20815f35..4a7ff8b0db20 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -308,13 +308,13 @@ HYPERVISOR_platform_op(struct xen_platform_op *op)
return _hypercall1(int, platform_op, op);
}
-static inline int
+static __always_inline int
HYPERVISOR_set_debugreg(int reg, unsigned long value)
{
return _hypercall2(int, set_debugreg, reg, value);
}
-static inline unsigned long
+static __always_inline unsigned long
HYPERVISOR_get_debugreg(int reg)
{
return _hypercall1(unsigned long, get_debugreg, reg);
@@ -358,7 +358,7 @@ HYPERVISOR_event_channel_op(int cmd, void *arg)
return _hypercall2(int, event_channel_op, cmd, arg);
}
-static inline int
+static __always_inline int
HYPERVISOR_xen_version(int cmd, void *arg)
{
return _hypercall2(int, xen_version, cmd, arg);
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index e9da3dc71254..23fb4d51a5da 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -29,6 +29,7 @@
#include <asm/io.h>
#include <asm/fixmap.h>
#include <asm/paravirt.h>
+#include <asm/asm-prototypes.h>
int __read_mostly alternatives_patched;
@@ -113,6 +114,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len)
}
}
+extern s32 __retpoline_sites[], __retpoline_sites_end[];
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
extern s32 __smp_locks[], __smp_locks_end[];
void text_poke_early(void *addr, const void *opcode, size_t len);
@@ -221,7 +223,7 @@ static __always_inline int optimize_nops_range(u8 *instr, u8 instrlen, int off)
* "noinline" to cause control flow change and thus invalidate I$ and
* cause refetch after modification.
*/
-static void __init_or_module noinline optimize_nops(struct alt_instr *a, u8 *instr)
+static void __init_or_module noinline optimize_nops(u8 *instr, size_t len)
{
struct insn insn;
int i = 0;
@@ -239,11 +241,11 @@ static void __init_or_module noinline optimize_nops(struct alt_instr *a, u8 *ins
* optimized.
*/
if (insn.length == 1 && insn.opcode.bytes[0] == 0x90)
- i += optimize_nops_range(instr, a->instrlen, i);
+ i += optimize_nops_range(instr, len, i);
else
i += insn.length;
- if (i >= a->instrlen)
+ if (i >= len)
return;
}
}
@@ -331,10 +333,185 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
text_poke_early(instr, insn_buff, insn_buff_sz);
next:
- optimize_nops(a, instr);
+ optimize_nops(instr, a->instrlen);
}
}
+#if defined(CONFIG_RETPOLINE) && defined(CONFIG_STACK_VALIDATION)
+
+/*
+ * CALL/JMP *%\reg
+ */
+static int emit_indirect(int op, int reg, u8 *bytes)
+{
+ int i = 0;
+ u8 modrm;
+
+ switch (op) {
+ case CALL_INSN_OPCODE:
+ modrm = 0x10; /* Reg = 2; CALL r/m */
+ break;
+
+ case JMP32_INSN_OPCODE:
+ modrm = 0x20; /* Reg = 4; JMP r/m */
+ break;
+
+ default:
+ WARN_ON_ONCE(1);
+ return -1;
+ }
+
+ if (reg >= 8) {
+ bytes[i++] = 0x41; /* REX.B prefix */
+ reg -= 8;
+ }
+
+ modrm |= 0xc0; /* Mod = 3 */
+ modrm += reg;
+
+ bytes[i++] = 0xff; /* opcode */
+ bytes[i++] = modrm;
+
+ return i;
+}
+
+/*
+ * Rewrite the compiler generated retpoline thunk calls.
+ *
+ * For spectre_v2=off (!X86_FEATURE_RETPOLINE), rewrite them into immediate
+ * indirect instructions, avoiding the extra indirection.
+ *
+ * For example, convert:
+ *
+ * CALL __x86_indirect_thunk_\reg
+ *
+ * into:
+ *
+ * CALL *%\reg
+ *
+ * It also tries to inline spectre_v2=retpoline,amd when size permits.
+ */
+static int patch_retpoline(void *addr, struct insn *insn, u8 *bytes)
+{
+ retpoline_thunk_t *target;
+ int reg, ret, i = 0;
+ u8 op, cc;
+
+ target = addr + insn->length + insn->immediate.value;
+ reg = target - __x86_indirect_thunk_array;
+
+ if (WARN_ON_ONCE(reg & ~0xf))
+ return -1;
+
+ /* If anyone ever does: CALL/JMP *%rsp, we're in deep trouble. */
+ BUG_ON(reg == 4);
+
+ if (cpu_feature_enabled(X86_FEATURE_RETPOLINE) &&
+ !cpu_feature_enabled(X86_FEATURE_RETPOLINE_AMD))
+ return -1;
+
+ op = insn->opcode.bytes[0];
+
+ /*
+ * Convert:
+ *
+ * Jcc.d32 __x86_indirect_thunk_\reg
+ *
+ * into:
+ *
+ * Jncc.d8 1f
+ * [ LFENCE ]
+ * JMP *%\reg
+ * [ NOP ]
+ * 1:
+ */
+ /* Jcc.d32 second opcode byte is in the range: 0x80-0x8f */
+ if (op == 0x0f && (insn->opcode.bytes[1] & 0xf0) == 0x80) {
+ cc = insn->opcode.bytes[1] & 0xf;
+ cc ^= 1; /* invert condition */
+
+ bytes[i++] = 0x70 + cc; /* Jcc.d8 */
+ bytes[i++] = insn->length - 2; /* sizeof(Jcc.d8) == 2 */
+
+ /* Continue as if: JMP.d32 __x86_indirect_thunk_\reg */
+ op = JMP32_INSN_OPCODE;
+ }
+
+ /*
+ * For RETPOLINE_AMD: prepend the indirect CALL/JMP with an LFENCE.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_AMD)) {
+ bytes[i++] = 0x0f;
+ bytes[i++] = 0xae;
+ bytes[i++] = 0xe8; /* LFENCE */
+ }
+
+ ret = emit_indirect(op, reg, bytes + i);
+ if (ret < 0)
+ return ret;
+ i += ret;
+
+ for (; i < insn->length;)
+ bytes[i++] = BYTES_NOP1;
+
+ return i;
+}
+
+/*
+ * Generated by 'objtool --retpoline'.
+ */
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
+{
+ s32 *s;
+
+ for (s = start; s < end; s++) {
+ void *addr = (void *)s + *s;
+ struct insn insn;
+ int len, ret;
+ u8 bytes[16];
+ u8 op1, op2;
+
+ ret = insn_decode_kernel(&insn, addr);
+ if (WARN_ON_ONCE(ret < 0))
+ continue;
+
+ op1 = insn.opcode.bytes[0];
+ op2 = insn.opcode.bytes[1];
+
+ switch (op1) {
+ case CALL_INSN_OPCODE:
+ case JMP32_INSN_OPCODE:
+ break;
+
+ case 0x0f: /* escape */
+ if (op2 >= 0x80 && op2 <= 0x8f)
+ break;
+ fallthrough;
+ default:
+ WARN_ON_ONCE(1);
+ continue;
+ }
+
+ DPRINTK("retpoline at: %pS (%px) len: %d to: %pS",
+ addr, addr, insn.length,
+ addr + insn.length + insn.immediate.value);
+
+ len = patch_retpoline(addr, &insn, bytes);
+ if (len == insn.length) {
+ optimize_nops(bytes, len);
+ DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr);
+ DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr);
+ text_poke_early(addr, bytes, len);
+ }
+ }
+}
+
+#else /* !RETPOLINES || !CONFIG_STACK_VALIDATION */
+
+void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
+
+#endif /* CONFIG_RETPOLINE && CONFIG_STACK_VALIDATION */
+
#ifdef CONFIG_SMP
static void alternatives_smp_lock(const s32 *start, const s32 *end,
u8 *text, u8 *text_end)
@@ -643,6 +820,12 @@ void __init alternative_instructions(void)
apply_paravirt(__parainstructions, __parainstructions_end);
/*
+ * Rewrite the retpolines, must be done before alternatives since
+ * those can rewrite the retpoline thunks.
+ */
+ apply_retpolines(__retpoline_sites, __retpoline_sites_end);
+
+ /*
* Then patch alternatives, such that those paravirt calls that are in
* alternatives can be overwritten by their immediate fragments.
*/
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ecfca3bbcd96..ba43597f1027 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -882,13 +882,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
return SPECTRE_V2_CMD_AUTO;
}
- if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
- boot_cpu_data.x86_vendor != X86_VENDOR_HYGON &&
- boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
- pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
-
spec_v2_print_cond(mitigation_options[i].option,
mitigation_options[i].secure);
return cmd;
diff --git a/arch/x86/kernel/irqflags.S b/arch/x86/kernel/irqflags.S
index 8ef35063964b..760e1f293093 100644
--- a/arch/x86/kernel/irqflags.S
+++ b/arch/x86/kernel/irqflags.S
@@ -7,9 +7,11 @@
/*
* unsigned long native_save_fl(void)
*/
+.pushsection .noinstr.text, "ax"
SYM_FUNC_START(native_save_fl)
pushf
pop %_ASM_AX
ret
SYM_FUNC_END(native_save_fl)
+.popsection
EXPORT_SYMBOL(native_save_fl)
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 5e9a34b5bd74..169fb6f4cd2e 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -251,7 +251,8 @@ int module_finalize(const Elf_Ehdr *hdr,
struct module *me)
{
const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
- *para = NULL, *orc = NULL, *orc_ip = NULL;
+ *para = NULL, *orc = NULL, *orc_ip = NULL,
+ *retpolines = NULL;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
@@ -267,8 +268,14 @@ int module_finalize(const Elf_Ehdr *hdr,
orc = s;
if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
orc_ip = s;
+ if (!strcmp(".retpoline_sites", secstrings + s->sh_name))
+ retpolines = s;
}
+ if (retpolines) {
+ void *rseg = (void *)retpolines->sh_addr;
+ apply_retpolines(rseg, rseg + retpolines->sh_size);
+ }
if (alt) {
/* patch .altinstructions */
void *aseg = (void *)alt->sh_addr;
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 04cafc057bed..ebc45360ffd4 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -218,6 +218,36 @@ void paravirt_end_context_switch(struct task_struct *next)
if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
arch_enter_lazy_mmu_mode();
}
+
+static noinstr unsigned long pv_native_read_cr2(void)
+{
+ return native_read_cr2();
+}
+
+static noinstr void pv_native_write_cr2(unsigned long val)
+{
+ native_write_cr2(val);
+}
+
+static noinstr unsigned long pv_native_get_debugreg(int regno)
+{
+ return native_get_debugreg(regno);
+}
+
+static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
+{
+ native_set_debugreg(regno, val);
+}
+
+static noinstr void pv_native_irq_enable(void)
+{
+ native_irq_enable();
+}
+
+static noinstr void pv_native_irq_disable(void)
+{
+ native_irq_disable();
+}
#endif
enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
@@ -244,8 +274,8 @@ struct paravirt_patch_template pv_ops = {
#ifdef CONFIG_PARAVIRT_XXL
.cpu.cpuid = native_cpuid,
- .cpu.get_debugreg = native_get_debugreg,
- .cpu.set_debugreg = native_set_debugreg,
+ .cpu.get_debugreg = pv_native_get_debugreg,
+ .cpu.set_debugreg = pv_native_set_debugreg,
.cpu.read_cr0 = native_read_cr0,
.cpu.write_cr0 = native_write_cr0,
.cpu.write_cr4 = native_write_cr4,
@@ -281,8 +311,8 @@ struct paravirt_patch_template pv_ops = {
/* Irq ops. */
.irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
- .irq.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
- .irq.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
+ .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
+ .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
.irq.safe_halt = native_safe_halt,
.irq.halt = native_halt,
#endif /* CONFIG_PARAVIRT_XXL */
@@ -298,8 +328,8 @@ struct paravirt_patch_template pv_ops = {
.mmu.exit_mmap = paravirt_nop,
#ifdef CONFIG_PARAVIRT_XXL
- .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2),
- .mmu.write_cr2 = native_write_cr2,
+ .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2),
+ .mmu.write_cr2 = pv_native_write_cr2,
.mmu.read_cr3 = __native_read_cr3,
.mmu.write_cr3 = native_write_cr3,
@@ -371,9 +401,6 @@ struct paravirt_patch_template pv_ops = {
};
#ifdef CONFIG_PARAVIRT_XXL
-/* At this point, native_get/set_debugreg has real function entries */
-NOKPROBE_SYMBOL(native_get_debugreg);
-NOKPROBE_SYMBOL(native_set_debugreg);
NOKPROBE_SYMBOL(native_load_idt);
void (*paravirt_iret)(void) = native_iret;
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index bf1033a62e48..ff1e82ff52d9 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -64,7 +64,7 @@ static bool sev_es_negotiate_protocol(void)
static __always_inline void vc_ghcb_invalidate(struct ghcb *ghcb)
{
ghcb->save.sw_exit_code = 0;
- memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
+ __builtin_memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
}
static bool vc_decoding_needed(unsigned long exit_code)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index efd9e9ea17f2..3d6dc12d198f 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -272,6 +272,20 @@ SECTIONS
__parainstructions_end = .;
}
+#ifdef CONFIG_RETPOLINE
+ /*
+ * List of instructions that call/jmp/jcc to retpoline thunks
+ * __x86_indirect_thunk_*(). These instructions can be patched along
+ * with alternatives, after which the section can be freed.
+ */
+ . = ALIGN(8);
+ .retpoline_sites : AT(ADDR(.retpoline_sites) - LOAD_OFFSET) {
+ __retpoline_sites = .;
+ *(.retpoline_sites)
+ __retpoline_sites_end = .;
+ }
+#endif
+
/*
* struct alt_inst entries. From the header (alternative.h):
* "Alternative instructions for different CPU types or capabilities"
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 5d30db599e10..e63ac08115cf 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -218,12 +218,12 @@ DECLARE_PER_CPU(struct svm_cpu_data *, svm_data);
void recalc_intercepts(struct vcpu_svm *svm);
-static inline struct kvm_svm *to_kvm_svm(struct kvm *kvm)
+static __always_inline struct kvm_svm *to_kvm_svm(struct kvm *kvm)
{
return container_of(kvm, struct kvm_svm, kvm);
}
-static inline bool sev_guest(struct kvm *kvm)
+static __always_inline bool sev_guest(struct kvm *kvm)
{
#ifdef CONFIG_KVM_AMD_SEV
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
@@ -234,7 +234,7 @@ static inline bool sev_guest(struct kvm *kvm)
#endif
}
-static inline bool sev_es_guest(struct kvm *kvm)
+static __always_inline bool sev_es_guest(struct kvm *kvm)
{
#ifdef CONFIG_KVM_AMD_SEV
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
@@ -271,7 +271,7 @@ static inline bool vmcb_is_dirty(struct vmcb *vmcb, int bit)
return !test_bit(bit, (unsigned long *)&vmcb->control.clean);
}
-static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
+static __always_inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
{
return container_of(vcpu, struct vcpu_svm, vcpu);
}
diff --git a/arch/x86/kvm/svm/svm_ops.h b/arch/x86/kvm/svm/svm_ops.h
index 22e2b019de37..9430d6437c9f 100644
--- a/arch/x86/kvm/svm/svm_ops.h
+++ b/arch/x86/kvm/svm/svm_ops.h
@@ -56,12 +56,12 @@ static inline void invlpga(unsigned long addr, u32 asid)
* VMSAVE, VMLOAD, etc... is still controlled by the effective address size,
* hence 'unsigned long' instead of 'hpa_t'.
*/
-static inline void vmsave(unsigned long pa)
+static __always_inline void vmsave(unsigned long pa)
{
svm_asm1(vmsave, "a" (pa), "memory");
}
-static inline void vmload(unsigned long pa)
+static __always_inline void vmload(unsigned long pa)
{
svm_asm1(vmload, "a" (pa), "memory");
}
diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
index 152ab0aa82cf..16731d2cf231 100644
--- a/arch/x86/kvm/vmx/evmcs.h
+++ b/arch/x86/kvm/vmx/evmcs.h
@@ -93,7 +93,7 @@ static __always_inline int get_evmcs_offset(unsigned long field,
return evmcs_field->offset;
}
-static inline void evmcs_write64(unsigned long field, u64 value)
+static __always_inline void evmcs_write64(unsigned long field, u64 value)
{
u16 clean_field;
int offset = get_evmcs_offset(field, &clean_field);
@@ -183,7 +183,7 @@ static inline void evmcs_load(u64 phys_addr)
__init void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf);
#else /* !IS_ENABLED(CONFIG_HYPERV) */
-static inline void evmcs_write64(unsigned long field, u64 value) {}
+static __always_inline void evmcs_write64(unsigned long field, u64 value) {}
static inline void evmcs_write32(unsigned long field, u32 value) {}
static inline void evmcs_write16(unsigned long field, u16 value) {}
static inline u64 evmcs_read64(unsigned long field) { return 0; }
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index ec9922cba30a..cf0b39f97adc 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -28,46 +28,14 @@
.macro THUNK reg
- .align 32
-
-SYM_FUNC_START(__x86_indirect_thunk_\reg)
+ .align RETPOLINE_THUNK_SIZE
+SYM_INNER_LABEL(__x86_indirect_thunk_\reg, SYM_L_GLOBAL)
+ UNWIND_HINT_EMPTY
ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *%\reg), \
__stringify(RETPOLINE \reg), X86_FEATURE_RETPOLINE, \
__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *%\reg), X86_FEATURE_RETPOLINE_AMD
-SYM_FUNC_END(__x86_indirect_thunk_\reg)
-
-.endm
-
-/*
- * This generates .altinstr_replacement symbols for use by objtool. They,
- * however, must not actually live in .altinstr_replacement since that will be
- * discarded after init, but module alternatives will also reference these
- * symbols.
- *
- * Their names matches the "__x86_indirect_" prefix to mark them as retpolines.
- */
-.macro ALT_THUNK reg
-
- .align 1
-
-SYM_FUNC_START_NOALIGN(__x86_indirect_alt_call_\reg)
- ANNOTATE_RETPOLINE_SAFE
-1: call *%\reg
-2: .skip 5-(2b-1b), 0x90
-SYM_FUNC_END(__x86_indirect_alt_call_\reg)
-
-STACK_FRAME_NON_STANDARD(__x86_indirect_alt_call_\reg)
-
-SYM_FUNC_START_NOALIGN(__x86_indirect_alt_jmp_\reg)
- ANNOTATE_RETPOLINE_SAFE
-1: jmp *%\reg
-2: .skip 5-(2b-1b), 0x90
-SYM_FUNC_END(__x86_indirect_alt_jmp_\reg)
-
-STACK_FRAME_NON_STANDARD(__x86_indirect_alt_jmp_\reg)
-
.endm
/*
@@ -85,22 +53,16 @@ STACK_FRAME_NON_STANDARD(__x86_indirect_alt_jmp_\reg)
#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym)
#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg)
-#undef GEN
+ .align RETPOLINE_THUNK_SIZE
+SYM_CODE_START(__x86_indirect_thunk_array)
+
#define GEN(reg) THUNK reg
#include <asm/GEN-for-each-reg.h>
-
#undef GEN
-#define GEN(reg) EXPORT_THUNK(reg)
-#include <asm/GEN-for-each-reg.h>
-#undef GEN
-#define GEN(reg) ALT_THUNK reg
-#include <asm/GEN-for-each-reg.h>
+ .align RETPOLINE_THUNK_SIZE
+SYM_CODE_END(__x86_indirect_thunk_array)
-#undef GEN
-#define GEN(reg) __EXPORT_THUNK(__x86_indirect_alt_call_ ## reg)
+#define GEN(reg) EXPORT_THUNK(reg)
#include <asm/GEN-for-each-reg.h>
-
#undef GEN
-#define GEN(reg) __EXPORT_THUNK(__x86_indirect_alt_jmp_ ## reg)
-#include <asm/GEN-for-each-reg.h>
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 9ea57389c554..39c802525fce 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -15,7 +15,6 @@
#include <asm/set_memory.h>
#include <asm/nospec-branch.h>
#include <asm/text-patching.h>
-#include <asm/asm-prototypes.h>
static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
{
@@ -225,6 +224,14 @@ static void jit_fill_hole(void *area, unsigned int size)
struct jit_context {
int cleanup_addr; /* Epilogue code offset */
+
+ /*
+ * Program specific offsets of labels in the code; these rely on the
+ * JIT doing at least 2 passes, recording the position on the first
+ * pass, only to generate the correct offset on the second pass.
+ */
+ int tail_call_direct_label;
+ int tail_call_indirect_label;
};
/* Maximum number of bytes emitted while JITing one eBPF insn */
@@ -380,20 +387,23 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
return __bpf_arch_text_poke(ip, t, old_addr, new_addr, true);
}
-static int get_pop_bytes(bool *callee_regs_used)
+#define EMIT_LFENCE() EMIT3(0x0F, 0xAE, 0xE8)
+
+static void emit_indirect_jump(u8 **pprog, int reg, u8 *ip)
{
- int bytes = 0;
+ u8 *prog = *pprog;
- if (callee_regs_used[3])
- bytes += 2;
- if (callee_regs_used[2])
- bytes += 2;
- if (callee_regs_used[1])
- bytes += 2;
- if (callee_regs_used[0])
- bytes += 1;
+#ifdef CONFIG_RETPOLINE
+ if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_AMD)) {
+ EMIT_LFENCE();
+ EMIT2(0xFF, 0xE0 + reg);
+ } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
+ emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
+ } else
+#endif
+ EMIT2(0xFF, 0xE0 + reg);
- return bytes;
+ *pprog = prog;
}
/*
@@ -411,29 +421,12 @@ static int get_pop_bytes(bool *callee_regs_used)
* out:
*/
static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
- u32 stack_depth)
+ u32 stack_depth, u8 *ip,
+ struct jit_context *ctx)
{
int tcc_off = -4 - round_up(stack_depth, 8);
- u8 *prog = *pprog;
- int pop_bytes = 0;
- int off1 = 42;
- int off2 = 31;
- int off3 = 9;
-
- /* count the additional bytes used for popping callee regs from stack
- * that need to be taken into account for each of the offsets that
- * are used for bailing out of the tail call
- */
- pop_bytes = get_pop_bytes(callee_regs_used);
- off1 += pop_bytes;
- off2 += pop_bytes;
- off3 += pop_bytes;
-
- if (stack_depth) {
- off1 += 7;
- off2 += 7;
- off3 += 7;
- }
+ u8 *prog = *pprog, *start = *pprog;
+ int offset;
/*
* rdi - pointer to ctx
@@ -448,8 +441,9 @@ static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
EMIT2(0x89, 0xD2); /* mov edx, edx */
EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
offsetof(struct bpf_array, map.max_entries));
-#define OFFSET1 (off1 + RETPOLINE_RCX_BPF_JIT_SIZE) /* Number of bytes to jump */
- EMIT2(X86_JBE, OFFSET1); /* jbe out */
+
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JBE, offset); /* jbe out */
/*
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
@@ -457,8 +451,9 @@ static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
*/
EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
-#define OFFSET2 (off2 + RETPOLINE_RCX_BPF_JIT_SIZE)
- EMIT2(X86_JA, OFFSET2); /* ja out */
+
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JA, offset); /* ja out */
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
@@ -471,12 +466,11 @@ static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
* goto out;
*/
EMIT3(0x48, 0x85, 0xC9); /* test rcx,rcx */
-#define OFFSET3 (off3 + RETPOLINE_RCX_BPF_JIT_SIZE)
- EMIT2(X86_JE, OFFSET3); /* je out */
- *pprog = prog;
- pop_callee_regs(pprog, callee_regs_used);
- prog = *pprog;
+ offset = ctx->tail_call_indirect_label - (prog + 2 - start);
+ EMIT2(X86_JE, offset); /* je out */
+
+ pop_callee_regs(&prog, callee_regs_used);
EMIT1(0x58); /* pop rax */
if (stack_depth)
@@ -493,41 +487,21 @@ static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
* rdi == ctx (1st arg)
* rcx == prog->bpf_func + X86_TAIL_CALL_OFFSET
*/
- RETPOLINE_RCX_BPF_JIT();
+ emit_indirect_jump(&prog, 1 /* rcx */, ip + (prog - start));
/* out: */
+ ctx->tail_call_indirect_label = prog - start;
*pprog = prog;
}
static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
- u8 **pprog, int addr, u8 *image,
- bool *callee_regs_used, u32 stack_depth)
+ u8 **pprog, u8 *ip,
+ bool *callee_regs_used, u32 stack_depth,
+ struct jit_context *ctx)
{
int tcc_off = -4 - round_up(stack_depth, 8);
- u8 *prog = *pprog;
- int pop_bytes = 0;
- int off1 = 20;
- int poke_off;
-
- /* count the additional bytes used for popping callee regs to stack
- * that need to be taken into account for jump offset that is used for
- * bailing out from of the tail call when limit is reached
- */
- pop_bytes = get_pop_bytes(callee_regs_used);
- off1 += pop_bytes;
-
- /*
- * total bytes for:
- * - nop5/ jmpq $off
- * - pop callee regs
- * - sub rsp, $val if depth > 0
- * - pop rax
- */
- poke_off = X86_PATCH_SIZE + pop_bytes + 1;
- if (stack_depth) {
- poke_off += 7;
- off1 += 7;
- }
+ u8 *prog = *pprog, *start = *pprog;
+ int offset;
/*
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
@@ -535,28 +509,30 @@ static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
*/
EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
- EMIT2(X86_JA, off1); /* ja out */
+
+ offset = ctx->tail_call_direct_label - (prog + 2 - start);
+ EMIT2(X86_JA, offset); /* ja out */
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
- poke->tailcall_bypass = image + (addr - poke_off - X86_PATCH_SIZE);
+ poke->tailcall_bypass = ip + (prog - start);
poke->adj_off = X86_TAIL_CALL_OFFSET;
- poke->tailcall_target = image + (addr - X86_PATCH_SIZE);
+ poke->tailcall_target = ip + ctx->tail_call_direct_label - X86_PATCH_SIZE;
poke->bypass_addr = (u8 *)poke->tailcall_target + X86_PATCH_SIZE;
emit_jump(&prog, (u8 *)poke->tailcall_target + X86_PATCH_SIZE,
poke->tailcall_bypass);
- *pprog = prog;
- pop_callee_regs(pprog, callee_regs_used);
- prog = *pprog;
+ pop_callee_regs(&prog, callee_regs_used);
EMIT1(0x58); /* pop rax */
if (stack_depth)
EMIT3_off32(0x48, 0x81, 0xC4, round_up(stack_depth, 8));
memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
prog += X86_PATCH_SIZE;
+
/* out: */
+ ctx->tail_call_direct_label = prog - start;
*pprog = prog;
}
@@ -1222,8 +1198,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
/* speculation barrier */
case BPF_ST | BPF_NOSPEC:
if (boot_cpu_has(X86_FEATURE_XMM2))
- /* Emit 'lfence' */
- EMIT3(0x0F, 0xAE, 0xE8);
+ EMIT_LFENCE();
break;
/* ST: *(u8*)(dst_reg + off) = imm */
@@ -1412,13 +1387,16 @@ st: if (is_imm8(insn->off))
case BPF_JMP | BPF_TAIL_CALL:
if (imm32)
emit_bpf_tail_call_direct(&bpf_prog->aux->poke_tab[imm32 - 1],
- &prog, addrs[i], image,
+ &prog, image + addrs[i - 1],
callee_regs_used,
- bpf_prog->aux->stack_depth);
+ bpf_prog->aux->stack_depth,
+ ctx);
else
emit_bpf_tail_call_indirect(&prog,
callee_regs_used,
- bpf_prog->aux->stack_depth);
+ bpf_prog->aux->stack_depth,
+ image + addrs[i - 1],
+ ctx);
break;
/* cond jump */
@@ -2124,24 +2102,6 @@ cleanup:
return ret;
}
-static int emit_fallback_jump(u8 **pprog)
-{
- u8 *prog = *pprog;
- int err = 0;
-
-#ifdef CONFIG_RETPOLINE
- /* Note that this assumes the the compiler uses external
- * thunks for indirect calls. Both clang and GCC use the same
- * naming convention for external thunks.
- */
- err = emit_jump(&prog, __x86_indirect_thunk_rdx, prog);
-#else
- EMIT2(0xFF, 0xE2); /* jmp rdx */
-#endif
- *pprog = prog;
- return err;
-}
-
static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs)
{
u8 *jg_reloc, *prog = *pprog;
@@ -2163,9 +2123,7 @@ static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs)
if (err)
return err;
- err = emit_fallback_jump(&prog); /* jmp thunk/indirect */
- if (err)
- return err;
+ emit_indirect_jump(&prog, 2 /* rdx */, prog);
*pprog = prog;
return 0;
diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index 3bfda5f502cb..da9b7cfa4632 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -15,6 +15,7 @@
#include <asm/cacheflush.h>
#include <asm/set_memory.h>
#include <asm/nospec-branch.h>
+#include <asm/asm-prototypes.h>
#include <linux/bpf.h>
/*
@@ -1267,6 +1268,21 @@ static void emit_epilogue(u8 **pprog, u32 stack_depth)
*pprog = prog;
}
+static int emit_jmp_edx(u8 **pprog, u8 *ip)
+{
+ u8 *prog = *pprog;
+ int cnt = 0;
+
+#ifdef CONFIG_RETPOLINE
+ EMIT1_off32(0xE9, (u8 *)__x86_indirect_thunk_edx - (ip + 5));
+#else
+ EMIT2(0xFF, 0xE2);
+#endif
+ *pprog = prog;
+
+ return cnt;
+}
+
/*
* Generate the following code:
* ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
@@ -1280,7 +1296,7 @@ static void emit_epilogue(u8 **pprog, u32 stack_depth)
* goto *(prog->bpf_func + prologue_size);
* out:
*/
-static void emit_bpf_tail_call(u8 **pprog)
+static void emit_bpf_tail_call(u8 **pprog, u8 *ip)
{
u8 *prog = *pprog;
int cnt = 0;
@@ -1362,7 +1378,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* eax == ctx (1st arg)
* edx == prog->bpf_func + prologue_size
*/
- RETPOLINE_EDX_BPF_JIT();
+ cnt += emit_jmp_edx(&prog, ip + cnt);
if (jmp_label1 == -1)
jmp_label1 = cnt;
@@ -2122,7 +2138,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
break;
}
case BPF_JMP | BPF_TAIL_CALL:
- emit_bpf_tail_call(&prog);
+ emit_bpf_tail_call(&prog, image + addrs[i - 1]);
break;
/* cond jump */
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index a7b7d674f500..4f63117f09bb 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -283,12 +283,12 @@ static void __init xen_init_capabilities(void)
}
}
-static void xen_set_debugreg(int reg, unsigned long val)
+static noinstr void xen_set_debugreg(int reg, unsigned long val)
{
HYPERVISOR_set_debugreg(reg, val);
}
-static unsigned long xen_get_debugreg(int reg)
+static noinstr unsigned long xen_get_debugreg(int reg)
{
return HYPERVISOR_get_debugreg(reg);
}
@@ -1025,52 +1025,54 @@ static const struct pv_info xen_info __initconst = {
.name = "Xen",
};
-static const struct pv_cpu_ops xen_cpu_ops __initconst = {
- .cpuid = xen_cpuid,
+static const typeof(pv_ops) xen_cpu_ops __initconst = {
+ .cpu = {
+ .cpuid = xen_cpuid,
- .set_debugreg = xen_set_debugreg,
- .get_debugreg = xen_get_debugreg,
+ .set_debugreg = xen_set_debugreg,
+ .get_debugreg = xen_get_debugreg,
- .read_cr0 = xen_read_cr0,
- .write_cr0 = xen_write_cr0,
+ .read_cr0 = xen_read_cr0,
+ .write_cr0 = xen_write_cr0,
- .write_cr4 = xen_write_cr4,
+ .write_cr4 = xen_write_cr4,
- .wbinvd = native_wbinvd,
+ .wbinvd = native_wbinvd,
- .read_msr = xen_read_msr,
- .write_msr = xen_write_msr,
+ .read_msr = xen_read_msr,
+ .write_msr = xen_write_msr,
- .read_msr_safe = xen_read_msr_safe,
- .write_msr_safe = xen_write_msr_safe,
+ .read_msr_safe = xen_read_msr_safe,
+ .write_msr_safe = xen_write_msr_safe,
- .read_pmc = xen_read_pmc,
+ .read_pmc = xen_read_pmc,
- .load_tr_desc = paravirt_nop,
- .set_ldt = xen_set_ldt,
- .load_gdt = xen_load_gdt,
- .load_idt = xen_load_idt,
- .load_tls = xen_load_tls,
- .load_gs_index = xen_load_gs_index,
+ .load_tr_desc = paravirt_nop,
+ .set_ldt = xen_set_ldt,
+ .load_gdt = xen_load_gdt,
+ .load_idt = xen_load_idt,
+ .load_tls = xen_load_tls,
+ .load_gs_index = xen_load_gs_index,
- .alloc_ldt = xen_alloc_ldt,
- .free_ldt = xen_free_ldt,
+ .alloc_ldt = xen_alloc_ldt,
+ .free_ldt = xen_free_ldt,
- .store_tr = xen_store_tr,
+ .store_tr = xen_store_tr,
- .write_ldt_entry = xen_write_ldt_entry,
- .write_gdt_entry = xen_write_gdt_entry,
- .write_idt_entry = xen_write_idt_entry,
- .load_sp0 = xen_load_sp0,
+ .write_ldt_entry = xen_write_ldt_entry,
+ .write_gdt_entry = xen_write_gdt_entry,
+ .write_idt_entry = xen_write_idt_entry,
+ .load_sp0 = xen_load_sp0,
#ifdef CONFIG_X86_IOPL_IOPERM
- .invalidate_io_bitmap = xen_invalidate_io_bitmap,
- .update_io_bitmap = xen_update_io_bitmap,
+ .invalidate_io_bitmap = xen_invalidate_io_bitmap,
+ .update_io_bitmap = xen_update_io_bitmap,
#endif
- .io_delay = xen_io_delay,
+ .io_delay = xen_io_delay,
- .start_context_switch = paravirt_start_context_switch,
- .end_context_switch = xen_end_context_switch,
+ .start_context_switch = paravirt_start_context_switch,
+ .end_context_switch = xen_end_context_switch,
+ },
};
static void xen_restart(char *msg)
@@ -1211,7 +1213,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Install Xen paravirt ops */
pv_info = xen_info;
- pv_ops.cpu = xen_cpu_ops;
+ pv_ops.cpu = xen_cpu_ops.cpu;
paravirt_iret = xen_iret;
xen_init_irq_ops();
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index dfa091d79c2e..4fe387e520af 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -19,12 +19,12 @@
* callback mask. We do this in a very simple manner, by making a call
* down into Xen. The pending flag will be checked by Xen on return.
*/
-void xen_force_evtchn_callback(void)
+noinstr void xen_force_evtchn_callback(void)
{
(void)HYPERVISOR_xen_version(0, NULL);
}
-asmlinkage __visible unsigned long xen_save_fl(void)
+asmlinkage __visible noinstr unsigned long xen_save_fl(void)
{
struct vcpu_info *vcpu;
unsigned long flags;
@@ -40,9 +40,9 @@ asmlinkage __visible unsigned long xen_save_fl(void)
*/
return (-flags) & X86_EFLAGS_IF;
}
-PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
+__PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl, ".noinstr.text");
-asmlinkage __visible void xen_irq_disable(void)
+asmlinkage __visible noinstr void xen_irq_disable(void)
{
/* There's a one instruction preempt window here. We need to
make sure we're don't switch CPUs between getting the vcpu
@@ -51,9 +51,9 @@ asmlinkage __visible void xen_irq_disable(void)
this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
preempt_enable_no_resched();
}
-PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
+__PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable, ".noinstr.text");
-asmlinkage __visible void xen_irq_enable(void)
+asmlinkage __visible noinstr void xen_irq_enable(void)
{
struct vcpu_info *vcpu;
@@ -76,7 +76,7 @@ asmlinkage __visible void xen_irq_enable(void)
preempt_enable();
}
-PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
+__PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable, ".noinstr.text");
static void xen_safe_halt(void)
{
@@ -94,17 +94,20 @@ static void xen_halt(void)
xen_safe_halt();
}
-static const struct pv_irq_ops xen_irq_ops __initconst = {
- .save_fl = PV_CALLEE_SAVE(xen_save_fl),
- .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
- .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
+static const typeof(pv_ops) xen_irq_ops __initconst = {
+ .irq = {
- .safe_halt = xen_safe_halt,
- .halt = xen_halt,
+ .save_fl = PV_CALLEE_SAVE(xen_save_fl),
+ .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
+ .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
+
+ .safe_halt = xen_safe_halt,
+ .halt = xen_halt,
+ },
};
void __init xen_init_irq_ops(void)
{
- pv_ops.irq = xen_irq_ops;
+ pv_ops.irq = xen_irq_ops.irq;
x86_init.irqs.intr_init = xen_init_IRQ;
}
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 3359c23573c5..1ce436eeda15 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1204,7 +1204,8 @@ static void __init xen_pagetable_init(void)
xen_remap_memory();
xen_setup_mfn_list_list();
}
-static void xen_write_cr2(unsigned long cr2)
+
+static noinstr void xen_write_cr2(unsigned long cr2)
{
this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
}
@@ -2078,67 +2079,69 @@ static void xen_leave_lazy_mmu(void)
preempt_enable();
}
-static const struct pv_mmu_ops xen_mmu_ops __initconst = {
- .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
- .write_cr2 = xen_write_cr2,
+static const typeof(pv_ops) xen_mmu_ops __initconst = {
+ .mmu = {
+ .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
+ .write_cr2 = xen_write_cr2,
- .read_cr3 = xen_read_cr3,
- .write_cr3 = xen_write_cr3_init,
+ .read_cr3 = xen_read_cr3,
+ .write_cr3 = xen_write_cr3_init,
- .flush_tlb_user = xen_flush_tlb,
- .flush_tlb_kernel = xen_flush_tlb,
- .flush_tlb_one_user = xen_flush_tlb_one_user,
- .flush_tlb_multi = xen_flush_tlb_multi,
- .tlb_remove_table = tlb_remove_table,
+ .flush_tlb_user = xen_flush_tlb,
+ .flush_tlb_kernel = xen_flush_tlb,
+ .flush_tlb_one_user = xen_flush_tlb_one_user,
+ .flush_tlb_multi = xen_flush_tlb_multi,
+ .tlb_remove_table = tlb_remove_table,
- .pgd_alloc = xen_pgd_alloc,
- .pgd_free = xen_pgd_free,
+ .pgd_alloc = xen_pgd_alloc,
+ .pgd_free = xen_pgd_free,
- .alloc_pte = xen_alloc_pte_init,
- .release_pte = xen_release_pte_init,
- .alloc_pmd = xen_alloc_pmd_init,
- .release_pmd = xen_release_pmd_init,
+ .alloc_pte = xen_alloc_pte_init,
+ .release_pte = xen_release_pte_init,
+ .alloc_pmd = xen_alloc_pmd_init,
+ .release_pmd = xen_release_pmd_init,
- .set_pte = xen_set_pte_init,
- .set_pmd = xen_set_pmd_hyper,
+ .set_pte = xen_set_pte_init,
+ .set_pmd = xen_set_pmd_hyper,
- .ptep_modify_prot_start = xen_ptep_modify_prot_start,
- .ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
+ .ptep_modify_prot_start = xen_ptep_modify_prot_start,
+ .ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
- .pte_val = PV_CALLEE_SAVE(xen_pte_val),
- .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
+ .pte_val = PV_CALLEE_SAVE(xen_pte_val),
+ .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
- .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
- .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
+ .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
+ .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
- .set_pud = xen_set_pud_hyper,
+ .set_pud = xen_set_pud_hyper,
- .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
- .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
+ .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
+ .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
- .pud_val = PV_CALLEE_SAVE(xen_pud_val),
- .make_pud = PV_CALLEE_SAVE(xen_make_pud),
- .set_p4d = xen_set_p4d_hyper,
+ .pud_val = PV_CALLEE_SAVE(xen_pud_val),
+ .make_pud = PV_CALLEE_SAVE(xen_make_pud),
+ .set_p4d = xen_set_p4d_hyper,
- .alloc_pud = xen_alloc_pmd_init,
- .release_pud = xen_release_pmd_init,
+ .alloc_pud = xen_alloc_pmd_init,
+ .release_pud = xen_release_pmd_init,
#if CONFIG_PGTABLE_LEVELS >= 5
- .p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
- .make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
+ .p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
+ .make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
#endif
- .activate_mm = xen_activate_mm,
- .dup_mmap = xen_dup_mmap,
- .exit_mmap = xen_exit_mmap,
+ .activate_mm = xen_activate_mm,
+ .dup_mmap = xen_dup_mmap,
+ .exit_mmap = xen_exit_mmap,
- .lazy_mode = {
- .enter = paravirt_enter_lazy_mmu,
- .leave = xen_leave_lazy_mmu,
- .flush = paravirt_flush_lazy_mmu,
- },
+ .lazy_mode = {
+ .enter = paravirt_enter_lazy_mmu,
+ .leave = xen_leave_lazy_mmu,
+ .flush = paravirt_flush_lazy_mmu,
+ },
- .set_fixmap = xen_set_fixmap,
+ .set_fixmap = xen_set_fixmap,
+ },
};
void __init xen_init_mmu_ops(void)
@@ -2146,7 +2149,7 @@ void __init xen_init_mmu_ops(void)
x86_init.paging.pagetable_init = xen_pagetable_init;
x86_init.hyper.init_after_bootmem = xen_after_bootmem;
- pv_ops.mmu = xen_mmu_ops;
+ pv_ops.mmu = xen_mmu_ops.mmu;
memset(dummy_mapping, 0xff, PAGE_SIZE);
}
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 1e626444712b..220dd9678494 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -21,6 +21,45 @@
#include <linux/init.h>
#include <linux/linkage.h>
+.pushsection .noinstr.text, "ax"
+/*
+ * Disabling events is simply a matter of making the event mask
+ * non-zero.
+ */
+SYM_FUNC_START(xen_irq_disable_direct)
+ movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+ ret
+SYM_FUNC_END(xen_irq_disable_direct)
+
+/*
+ * Force an event check by making a hypercall, but preserve regs
+ * before making the call.
+ */
+SYM_FUNC_START(check_events)
+ FRAME_BEGIN
+ push %rax
+ push %rcx
+ push %rdx
+ push %rsi
+ push %rdi
+ push %r8
+ push %r9
+ push %r10
+ push %r11
+ call xen_force_evtchn_callback
+ pop %r11
+ pop %r10
+ pop %r9
+ pop %r8
+ pop %rdi
+ pop %rsi
+ pop %rdx
+ pop %rcx
+ pop %rax
+ FRAME_END
+ ret
+SYM_FUNC_END(check_events)
+
/*
* Enable events. This clears the event mask and tests the pending
* event status with one and operation. If there are pending events,
@@ -47,16 +86,6 @@ SYM_FUNC_START(xen_irq_enable_direct)
ret
SYM_FUNC_END(xen_irq_enable_direct)
-
-/*
- * Disabling events is simply a matter of making the event mask
- * non-zero.
- */
-SYM_FUNC_START(xen_irq_disable_direct)
- movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
- ret
-SYM_FUNC_END(xen_irq_disable_direct)
-
/*
* (xen_)save_fl is used to get the current interrupt enable status.
* Callers expect the status to be in X86_EFLAGS_IF, and other bits
@@ -73,35 +102,6 @@ SYM_FUNC_START(xen_save_fl_direct)
ret
SYM_FUNC_END(xen_save_fl_direct)
-/*
- * Force an event check by making a hypercall, but preserve regs
- * before making the call.
- */
-SYM_FUNC_START(check_events)
- FRAME_BEGIN
- push %rax
- push %rcx
- push %rdx
- push %rsi
- push %rdi
- push %r8
- push %r9
- push %r10
- push %r11
- call xen_force_evtchn_callback
- pop %r11
- pop %r10
- pop %r9
- pop %r8
- pop %rdi
- pop %rsi
- pop %rdx
- pop %rcx
- pop %rax
- FRAME_END
- ret
-SYM_FUNC_END(check_events)
-
SYM_FUNC_START(xen_read_cr2)
FRAME_BEGIN
_ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX
@@ -116,6 +116,7 @@ SYM_FUNC_START(xen_read_cr2_direct)
FRAME_END
ret
SYM_FUNC_END(xen_read_cr2_direct);
+.popsection
.macro xen_pv_trap name
SYM_CODE_START(xen_\name)
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index cb6538ae2fe0..9e27b86a0c31 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -20,6 +20,23 @@
#include <xen/interface/xen-mca.h>
#include <asm/xen/interface.h>
+.pushsection .noinstr.text, "ax"
+ .balign PAGE_SIZE
+SYM_CODE_START(hypercall_page)
+ .rept (PAGE_SIZE / 32)
+ UNWIND_HINT_FUNC
+ .skip 31, 0x90
+ ret
+ .endr
+
+#define HYPERCALL(n) \
+ .equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
+ .type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
+#include <asm/xen-hypercalls.h>
+#undef HYPERCALL
+SYM_CODE_END(hypercall_page)
+.popsection
+
#ifdef CONFIG_XEN_PV
__INIT
SYM_CODE_START(startup_xen)
@@ -64,23 +81,6 @@ SYM_CODE_END(asm_cpu_bringup_and_idle)
#endif
#endif
-.pushsection .text
- .balign PAGE_SIZE
-SYM_CODE_START(hypercall_page)
- .rept (PAGE_SIZE / 32)
- UNWIND_HINT_FUNC
- .skip 31, 0x90
- ret
- .endr
-
-#define HYPERCALL(n) \
- .equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
- .type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32
-#include <asm/xen-hypercalls.h>
-#undef HYPERCALL
-SYM_CODE_END(hypercall_page)
-.popsection
-
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")