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-rw-r--r--arch/x86/entry/Makefile4
-rw-r--r--arch/x86/entry/calling.h33
-rw-r--r--arch/x86/entry/entry_32.S141
-rw-r--r--arch/x86/entry/entry_64.S16
-rw-r--r--arch/x86/entry/vdso/vma.c10
5 files changed, 127 insertions, 77 deletions
diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile
index 77f28ce9c646..9976fcecd17e 100644
--- a/arch/x86/entry/Makefile
+++ b/arch/x86/entry/Makefile
@@ -5,8 +5,8 @@
OBJECT_FILES_NON_STANDARD_entry_$(BITS).o := y
OBJECT_FILES_NON_STANDARD_entry_64_compat.o := y
-CFLAGS_syscall_64.o += -Wno-override-init
-CFLAGS_syscall_32.o += -Wno-override-init
+CFLAGS_syscall_64.o += $(call cc-option,-Wno-override-init,)
+CFLAGS_syscall_32.o += $(call cc-option,-Wno-override-init,)
obj-y := entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o
obj-y += common.o
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 9a9e5884066c..05ed3d393da7 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -90,8 +90,8 @@ For 32-bit we have the following conventions - kernel is built with
#define SIZEOF_PTREGS 21*8
- .macro ALLOC_PT_GPREGS_ON_STACK addskip=0
- addq $-(15*8+\addskip), %rsp
+ .macro ALLOC_PT_GPREGS_ON_STACK
+ addq $-(15*8), %rsp
.endm
.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
@@ -147,15 +147,6 @@ For 32-bit we have the following conventions - kernel is built with
movq 5*8+\offset(%rsp), %rbx
.endm
- .macro ZERO_EXTRA_REGS
- xorl %r15d, %r15d
- xorl %r14d, %r14d
- xorl %r13d, %r13d
- xorl %r12d, %r12d
- xorl %ebp, %ebp
- xorl %ebx, %ebx
- .endm
-
.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
.if \rstor_r11
movq 6*8(%rsp), %r11
@@ -201,6 +192,26 @@ For 32-bit we have the following conventions - kernel is built with
.byte 0xf1
.endm
+/*
+ * This is a sneaky trick to help the unwinder find pt_regs on the stack. The
+ * frame pointer is replaced with an encoded pointer to pt_regs. The encoding
+ * is just setting the LSB, which makes it an invalid stack address and is also
+ * a signal to the unwinder that it's a pt_regs pointer in disguise.
+ *
+ * NOTE: This macro must be used *after* SAVE_EXTRA_REGS because it corrupts
+ * the original rbp.
+ */
+.macro ENCODE_FRAME_POINTER ptregs_offset=0
+#ifdef CONFIG_FRAME_POINTER
+ .if \ptregs_offset
+ leaq \ptregs_offset(%rsp), %rbp
+ .else
+ mov %rsp, %rbp
+ .endif
+ orq $0x1, %rbp
+#endif
+.endm
+
#endif /* CONFIG_X86_64 */
/*
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 21b352a11b49..acc0c6f36f3f 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -45,6 +45,7 @@
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/export.h>
+#include <asm/frame.h>
.section .entry.text, "ax"
@@ -175,6 +176,22 @@
SET_KERNEL_GS %edx
.endm
+/*
+ * This is a sneaky trick to help the unwinder find pt_regs on the stack. The
+ * frame pointer is replaced with an encoded pointer to pt_regs. The encoding
+ * is just setting the LSB, which makes it an invalid stack address and is also
+ * a signal to the unwinder that it's a pt_regs pointer in disguise.
+ *
+ * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the
+ * original rbp.
+ */
+.macro ENCODE_FRAME_POINTER
+#ifdef CONFIG_FRAME_POINTER
+ mov %esp, %ebp
+ orl $0x1, %ebp
+#endif
+.endm
+
.macro RESTORE_INT_REGS
popl %ebx
popl %ecx
@@ -238,6 +255,23 @@ ENTRY(__switch_to_asm)
END(__switch_to_asm)
/*
+ * The unwinder expects the last frame on the stack to always be at the same
+ * offset from the end of the page, which allows it to validate the stack.
+ * Calling schedule_tail() directly would break that convention because its an
+ * asmlinkage function so its argument has to be pushed on the stack. This
+ * wrapper creates a proper "end of stack" frame header before the call.
+ */
+ENTRY(schedule_tail_wrapper)
+ FRAME_BEGIN
+
+ pushl %eax
+ call schedule_tail
+ popl %eax
+
+ FRAME_END
+ ret
+ENDPROC(schedule_tail_wrapper)
+/*
* A newly forked process directly context switches into this address.
*
* eax: prev task we switched from
@@ -245,9 +279,7 @@ END(__switch_to_asm)
* edi: kernel thread arg
*/
ENTRY(ret_from_fork)
- pushl %eax
- call schedule_tail
- popl %eax
+ call schedule_tail_wrapper
testl %ebx, %ebx
jnz 1f /* kernel threads are uncommon */
@@ -307,13 +339,13 @@ END(ret_from_exception)
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
DISABLE_INTERRUPTS(CLBR_ANY)
-need_resched:
+.Lneed_resched:
cmpl $0, PER_CPU_VAR(__preempt_count)
jnz restore_all
testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
call preempt_schedule_irq
- jmp need_resched
+ jmp .Lneed_resched
END(resume_kernel)
#endif
@@ -334,7 +366,7 @@ GLOBAL(__begin_SYSENTER_singlestep_region)
*/
ENTRY(xen_sysenter_target)
addl $5*4, %esp /* remove xen-provided frame */
- jmp sysenter_past_esp
+ jmp .Lsysenter_past_esp
#endif
/*
@@ -371,7 +403,7 @@ ENTRY(xen_sysenter_target)
*/
ENTRY(entry_SYSENTER_32)
movl TSS_sysenter_sp0(%esp), %esp
-sysenter_past_esp:
+.Lsysenter_past_esp:
pushl $__USER_DS /* pt_regs->ss */
pushl %ebp /* pt_regs->sp (stashed in bp) */
pushfl /* pt_regs->flags (except IF = 0) */
@@ -504,9 +536,9 @@ ENTRY(entry_INT80_32)
restore_all:
TRACE_IRQS_IRET
-restore_all_notrace:
+.Lrestore_all_notrace:
#ifdef CONFIG_X86_ESPFIX32
- ALTERNATIVE "jmp restore_nocheck", "", X86_BUG_ESPFIX
+ ALTERNATIVE "jmp .Lrestore_nocheck", "", X86_BUG_ESPFIX
movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
/*
@@ -518,22 +550,23 @@ restore_all_notrace:
movb PT_CS(%esp), %al
andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
- je ldt_ss # returning to user-space with LDT SS
+ je .Lldt_ss # returning to user-space with LDT SS
#endif
-restore_nocheck:
+.Lrestore_nocheck:
RESTORE_REGS 4 # skip orig_eax/error_code
-irq_return:
+.Lirq_return:
INTERRUPT_RETURN
+
.section .fixup, "ax"
ENTRY(iret_exc )
pushl $0 # no error code
pushl $do_iret_error
- jmp error_code
+ jmp common_exception
.previous
- _ASM_EXTABLE(irq_return, iret_exc)
+ _ASM_EXTABLE(.Lirq_return, iret_exc)
#ifdef CONFIG_X86_ESPFIX32
-ldt_ss:
+.Lldt_ss:
/*
* Setup and switch to ESPFIX stack
*
@@ -562,7 +595,7 @@ ldt_ss:
*/
DISABLE_INTERRUPTS(CLBR_EAX)
lss (%esp), %esp /* switch to espfix segment */
- jmp restore_nocheck
+ jmp .Lrestore_nocheck
#endif
ENDPROC(entry_INT80_32)
@@ -624,6 +657,7 @@ common_interrupt:
ASM_CLAC
addl $-0x80, (%esp) /* Adjust vector into the [-256, -1] range */
SAVE_ALL
+ ENCODE_FRAME_POINTER
TRACE_IRQS_OFF
movl %esp, %eax
call do_IRQ
@@ -635,6 +669,7 @@ ENTRY(name) \
ASM_CLAC; \
pushl $~(nr); \
SAVE_ALL; \
+ ENCODE_FRAME_POINTER; \
TRACE_IRQS_OFF \
movl %esp, %eax; \
call fn; \
@@ -659,7 +694,7 @@ ENTRY(coprocessor_error)
ASM_CLAC
pushl $0
pushl $do_coprocessor_error
- jmp error_code
+ jmp common_exception
END(coprocessor_error)
ENTRY(simd_coprocessor_error)
@@ -673,14 +708,14 @@ ENTRY(simd_coprocessor_error)
#else
pushl $do_simd_coprocessor_error
#endif
- jmp error_code
+ jmp common_exception
END(simd_coprocessor_error)
ENTRY(device_not_available)
ASM_CLAC
pushl $-1 # mark this as an int
pushl $do_device_not_available
- jmp error_code
+ jmp common_exception
END(device_not_available)
#ifdef CONFIG_PARAVIRT
@@ -694,59 +729,59 @@ ENTRY(overflow)
ASM_CLAC
pushl $0
pushl $do_overflow
- jmp error_code
+ jmp common_exception
END(overflow)
ENTRY(bounds)
ASM_CLAC
pushl $0
pushl $do_bounds
- jmp error_code
+ jmp common_exception
END(bounds)
ENTRY(invalid_op)
ASM_CLAC
pushl $0
pushl $do_invalid_op
- jmp error_code
+ jmp common_exception
END(invalid_op)
ENTRY(coprocessor_segment_overrun)
ASM_CLAC
pushl $0
pushl $do_coprocessor_segment_overrun
- jmp error_code
+ jmp common_exception
END(coprocessor_segment_overrun)
ENTRY(invalid_TSS)
ASM_CLAC
pushl $do_invalid_TSS
- jmp error_code
+ jmp common_exception
END(invalid_TSS)
ENTRY(segment_not_present)
ASM_CLAC
pushl $do_segment_not_present
- jmp error_code
+ jmp common_exception
END(segment_not_present)
ENTRY(stack_segment)
ASM_CLAC
pushl $do_stack_segment
- jmp error_code
+ jmp common_exception
END(stack_segment)
ENTRY(alignment_check)
ASM_CLAC
pushl $do_alignment_check
- jmp error_code
+ jmp common_exception
END(alignment_check)
ENTRY(divide_error)
ASM_CLAC
pushl $0 # no error code
pushl $do_divide_error
- jmp error_code
+ jmp common_exception
END(divide_error)
#ifdef CONFIG_X86_MCE
@@ -754,7 +789,7 @@ ENTRY(machine_check)
ASM_CLAC
pushl $0
pushl machine_check_vector
- jmp error_code
+ jmp common_exception
END(machine_check)
#endif
@@ -762,13 +797,14 @@ ENTRY(spurious_interrupt_bug)
ASM_CLAC
pushl $0
pushl $do_spurious_interrupt_bug
- jmp error_code
+ jmp common_exception
END(spurious_interrupt_bug)
#ifdef CONFIG_XEN
ENTRY(xen_hypervisor_callback)
pushl $-1 /* orig_ax = -1 => not a system call */
SAVE_ALL
+ ENCODE_FRAME_POINTER
TRACE_IRQS_OFF
/*
@@ -823,6 +859,7 @@ ENTRY(xen_failsafe_callback)
jmp iret_exc
5: pushl $-1 /* orig_ax = -1 => not a system call */
SAVE_ALL
+ ENCODE_FRAME_POINTER
jmp ret_from_exception
.section .fixup, "ax"
@@ -882,7 +919,7 @@ ftrace_call:
popl %edx
popl %ecx
popl %eax
-ftrace_ret:
+.Lftrace_ret:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
ftrace_graph_call:
@@ -952,7 +989,7 @@ GLOBAL(ftrace_regs_call)
popl %gs
addl $8, %esp /* Skip orig_ax and ip */
popf /* Pop flags at end (no addl to corrupt flags) */
- jmp ftrace_ret
+ jmp .Lftrace_ret
popf
jmp ftrace_stub
@@ -963,7 +1000,7 @@ ENTRY(mcount)
jb ftrace_stub /* Paging not enabled yet? */
cmpl $ftrace_stub, ftrace_trace_function
- jnz trace
+ jnz .Ltrace
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
cmpl $ftrace_stub, ftrace_graph_return
jnz ftrace_graph_caller
@@ -976,7 +1013,7 @@ ftrace_stub:
ret
/* taken from glibc */
-trace:
+.Ltrace:
pushl %eax
pushl %ecx
pushl %edx
@@ -1027,7 +1064,7 @@ return_to_handler:
ENTRY(trace_page_fault)
ASM_CLAC
pushl $trace_do_page_fault
- jmp error_code
+ jmp common_exception
END(trace_page_fault)
#endif
@@ -1035,7 +1072,10 @@ ENTRY(page_fault)
ASM_CLAC
pushl $do_page_fault
ALIGN
-error_code:
+ jmp common_exception
+END(page_fault)
+
+common_exception:
/* the function address is in %gs's slot on the stack */
pushl %fs
pushl %es
@@ -1047,6 +1087,7 @@ error_code:
pushl %edx
pushl %ecx
pushl %ebx
+ ENCODE_FRAME_POINTER
cld
movl $(__KERNEL_PERCPU), %ecx
movl %ecx, %fs
@@ -1064,7 +1105,7 @@ error_code:
movl %esp, %eax # pt_regs pointer
call *%edi
jmp ret_from_exception
-END(page_fault)
+END(common_exception)
ENTRY(debug)
/*
@@ -1079,6 +1120,7 @@ ENTRY(debug)
ASM_CLAC
pushl $-1 # mark this as an int
SAVE_ALL
+ ENCODE_FRAME_POINTER
xorl %edx, %edx # error code 0
movl %esp, %eax # pt_regs pointer
@@ -1094,11 +1136,11 @@ ENTRY(debug)
.Ldebug_from_sysenter_stack:
/* We're on the SYSENTER stack. Switch off. */
- movl %esp, %ebp
+ movl %esp, %ebx
movl PER_CPU_VAR(cpu_current_top_of_stack), %esp
TRACE_IRQS_OFF
call do_debug
- movl %ebp, %esp
+ movl %ebx, %esp
jmp ret_from_exception
END(debug)
@@ -1116,11 +1158,12 @@ ENTRY(nmi)
movl %ss, %eax
cmpw $__ESPFIX_SS, %ax
popl %eax
- je nmi_espfix_stack
+ je .Lnmi_espfix_stack
#endif
pushl %eax # pt_regs->orig_ax
SAVE_ALL
+ ENCODE_FRAME_POINTER
xorl %edx, %edx # zero error code
movl %esp, %eax # pt_regs pointer
@@ -1132,21 +1175,21 @@ ENTRY(nmi)
/* Not on SYSENTER stack. */
call do_nmi
- jmp restore_all_notrace
+ jmp .Lrestore_all_notrace
.Lnmi_from_sysenter_stack:
/*
* We're on the SYSENTER stack. Switch off. No one (not even debug)
* is using the thread stack right now, so it's safe for us to use it.
*/
- movl %esp, %ebp
+ movl %esp, %ebx
movl PER_CPU_VAR(cpu_current_top_of_stack), %esp
call do_nmi
- movl %ebp, %esp
- jmp restore_all_notrace
+ movl %ebx, %esp
+ jmp .Lrestore_all_notrace
#ifdef CONFIG_X86_ESPFIX32
-nmi_espfix_stack:
+.Lnmi_espfix_stack:
/*
* create the pointer to lss back
*/
@@ -1159,12 +1202,13 @@ nmi_espfix_stack:
.endr
pushl %eax
SAVE_ALL
+ ENCODE_FRAME_POINTER
FIXUP_ESPFIX_STACK # %eax == %esp
xorl %edx, %edx # zero error code
call do_nmi
RESTORE_REGS
lss 12+4(%esp), %esp # back to espfix stack
- jmp irq_return
+ jmp .Lirq_return
#endif
END(nmi)
@@ -1172,6 +1216,7 @@ ENTRY(int3)
ASM_CLAC
pushl $-1 # mark this as an int
SAVE_ALL
+ ENCODE_FRAME_POINTER
TRACE_IRQS_OFF
xorl %edx, %edx # zero error code
movl %esp, %eax # pt_regs pointer
@@ -1181,14 +1226,14 @@ END(int3)
ENTRY(general_protection)
pushl $do_general_protection
- jmp error_code
+ jmp common_exception
END(general_protection)
#ifdef CONFIG_KVM_GUEST
ENTRY(async_page_fault)
ASM_CLAC
pushl $do_async_page_fault
- jmp error_code
+ jmp common_exception
END(async_page_fault)
#endif
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ef766a358b37..5b219707c2f2 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -38,12 +38,6 @@
#include <asm/export.h>
#include <linux/err.h>
-/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
-#include <linux/elf-em.h>
-#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
-#define __AUDIT_ARCH_64BIT 0x80000000
-#define __AUDIT_ARCH_LE 0x40000000
-
.code64
.section .entry.text, "ax"
@@ -469,6 +463,7 @@ END(irq_entries_start)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ ENCODE_FRAME_POINTER
testb $3, CS(%rsp)
jz 1f
@@ -985,6 +980,7 @@ ENTRY(xen_failsafe_callback)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ ENCODE_FRAME_POINTER
jmp error_exit
END(xen_failsafe_callback)
@@ -1028,6 +1024,7 @@ ENTRY(paranoid_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
rdmsr
@@ -1075,6 +1072,7 @@ ENTRY(error_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ ENCODE_FRAME_POINTER 8
xorl %ebx, %ebx
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@@ -1257,6 +1255,7 @@ ENTRY(nmi)
pushq %r13 /* pt_regs->r13 */
pushq %r14 /* pt_regs->r14 */
pushq %r15 /* pt_regs->r15 */
+ ENCODE_FRAME_POINTER
/*
* At this point we no longer need to worry about stack damage
@@ -1270,11 +1269,10 @@ ENTRY(nmi)
/*
* Return back to user mode. We must *not* do the normal exit
- * work, because we don't want to enable interrupts. Fortunately,
- * do_nmi doesn't modify pt_regs.
+ * work, because we don't want to enable interrupts.
*/
SWAPGS
- jmp restore_c_regs_and_iret
+ jmp restore_regs_and_iret
.Lnmi_from_kernel:
/*
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 23c881caabd1..e739002427ed 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -161,8 +161,6 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
}
text_start = addr - image->sym_vvar_start;
- current->mm->context.vdso = (void __user *)text_start;
- current->mm->context.vdso_image = image;
/*
* MAYWRITE to allow gdb to COW and set breakpoints
@@ -189,14 +187,12 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
do_munmap(mm, text_start, image->size);
+ } else {
+ current->mm->context.vdso = (void __user *)text_start;
+ current->mm->context.vdso_image = image;
}
up_fail:
- if (ret) {
- current->mm->context.vdso = NULL;
- current->mm->context.vdso_image = NULL;
- }
-
up_write(&mm->mmap_sem);
return ret;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-07 10:20:52 +0000