From 2a13c13b39a8aea4c69a31549e4cb0094f30103b Mon Sep 17 00:00:00 2001 From: Vanshidhar Konda Date: Fri, 30 Oct 2020 10:30:50 -0700 Subject: arm64: NUMA: Kconfig: Increase NODES_SHIFT to 4 The current arm64 default config limits max NUMA nodes available on system to 4 (NODES_SHIFT = 2). Today's arm64 systems can reach or exceed 16 NUMA nodes. To accomodate current hardware and to fit NODES_SHIFT within page flags on arm64, increase NODES_SHIFT to 4. Signed-off-by: Vanshidhar Konda Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20201020173409.1266576-1-vanshikonda@os.amperecomputing.com/ Link: https://lore.kernel.org/r/20201030173050.1182876-1-vanshikonda@os.amperecomputing.com Signed-off-by: Will Deacon --- arch/arm64/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1d466addb078..1515f6f153a0 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1002,7 +1002,7 @@ config NUMA config NODES_SHIFT int "Maximum NUMA Nodes (as a power of 2)" range 1 10 - default "2" + default "4" depends on NEED_MULTIPLE_NODES help Specify the maximum number of NUMA Nodes available on the target -- cgit v1.2.3 From 7ee31a3aa8f490c6507bc4294df6b70bed1c593e Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Tue, 3 Nov 2020 14:49:01 +0100 Subject: arm64: kprobes: Use BRK instead of single-step when executing instructions out-of-line Commit 36dadef23fcc ("kprobes: Init kprobes in early_initcall") enabled using kprobes from early_initcall. Unfortunately at this point the hardware debug infrastructure is not operational. The OS lock may still be locked, and the hardware watchpoints may have unknown values when kprobe enables debug monitors to single-step instructions. Rather than using hardware single-step, append a BRK instruction after the instruction to be executed out-of-line. Fixes: 36dadef23fcc ("kprobes: Init kprobes in early_initcall") Suggested-by: Will Deacon Signed-off-by: Jean-Philippe Brucker Acked-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20201103134900.337243-1-jean-philippe@linaro.org Signed-off-by: Will Deacon --- arch/arm64/include/asm/brk-imm.h | 2 + arch/arm64/include/asm/debug-monitors.h | 1 + arch/arm64/include/asm/kprobes.h | 2 +- arch/arm64/kernel/probes/kprobes.c | 69 +++++++++++---------------------- 4 files changed, 27 insertions(+), 47 deletions(-) diff --git a/arch/arm64/include/asm/brk-imm.h b/arch/arm64/include/asm/brk-imm.h index e3d47b52161d..ec7720dbe2c8 100644 --- a/arch/arm64/include/asm/brk-imm.h +++ b/arch/arm64/include/asm/brk-imm.h @@ -10,6 +10,7 @@ * #imm16 values used for BRK instruction generation * 0x004: for installing kprobes * 0x005: for installing uprobes + * 0x006: for kprobe software single-step * Allowed values for kgdb are 0x400 - 0x7ff * 0x100: for triggering a fault on purpose (reserved) * 0x400: for dynamic BRK instruction @@ -19,6 +20,7 @@ */ #define KPROBES_BRK_IMM 0x004 #define UPROBES_BRK_IMM 0x005 +#define KPROBES_BRK_SS_IMM 0x006 #define FAULT_BRK_IMM 0x100 #define KGDB_DYN_DBG_BRK_IMM 0x400 #define KGDB_COMPILED_DBG_BRK_IMM 0x401 diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 0b298f48f5bf..657c921fd784 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -53,6 +53,7 @@ /* kprobes BRK opcodes with ESR encoding */ #define BRK64_OPCODE_KPROBES (AARCH64_BREAK_MON | (KPROBES_BRK_IMM << 5)) +#define BRK64_OPCODE_KPROBES_SS (AARCH64_BREAK_MON | (KPROBES_BRK_SS_IMM << 5)) /* uprobes BRK opcodes with ESR encoding */ #define BRK64_OPCODE_UPROBES (AARCH64_BREAK_MON | (UPROBES_BRK_IMM << 5)) diff --git a/arch/arm64/include/asm/kprobes.h b/arch/arm64/include/asm/kprobes.h index 97e511d645a2..8699ce30f587 100644 --- a/arch/arm64/include/asm/kprobes.h +++ b/arch/arm64/include/asm/kprobes.h @@ -16,7 +16,7 @@ #include #define __ARCH_WANT_KPROBES_INSN_SLOT -#define MAX_INSN_SIZE 1 +#define MAX_INSN_SIZE 2 #define flush_insn_slot(p) do { } while (0) #define kretprobe_blacklist_size 0 diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index deba738142ed..f11a1a1f7026 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -36,25 +36,16 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); static void __kprobes post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); -static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode) -{ - void *addrs[1]; - u32 insns[1]; - - addrs[0] = addr; - insns[0] = opcode; - - return aarch64_insn_patch_text(addrs, insns, 1); -} - static void __kprobes arch_prepare_ss_slot(struct kprobe *p) { + kprobe_opcode_t *addr = p->ainsn.api.insn; + void *addrs[] = {addr, addr + 1}; + u32 insns[] = {p->opcode, BRK64_OPCODE_KPROBES_SS}; + /* prepare insn slot */ - patch_text(p->ainsn.api.insn, p->opcode); + aarch64_insn_patch_text(addrs, insns, 2); - flush_icache_range((uintptr_t) (p->ainsn.api.insn), - (uintptr_t) (p->ainsn.api.insn) + - MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + flush_icache_range((uintptr_t)addr, (uintptr_t)(addr + MAX_INSN_SIZE)); /* * Needs restoring of return address after stepping xol. @@ -128,13 +119,18 @@ void *alloc_insn_page(void) /* arm kprobe: install breakpoint in text */ void __kprobes arch_arm_kprobe(struct kprobe *p) { - patch_text(p->addr, BRK64_OPCODE_KPROBES); + void *addr = p->addr; + u32 insn = BRK64_OPCODE_KPROBES; + + aarch64_insn_patch_text(&addr, &insn, 1); } /* disarm kprobe: remove breakpoint from text */ void __kprobes arch_disarm_kprobe(struct kprobe *p) { - patch_text(p->addr, p->opcode); + void *addr = p->addr; + + aarch64_insn_patch_text(&addr, &p->opcode, 1); } void __kprobes arch_remove_kprobe(struct kprobe *p) @@ -163,20 +159,15 @@ static void __kprobes set_current_kprobe(struct kprobe *p) } /* - * Interrupts need to be disabled before single-step mode is set, and not - * reenabled until after single-step mode ends. - * Without disabling interrupt on local CPU, there is a chance of - * interrupt occurrence in the period of exception return and start of - * out-of-line single-step, that result in wrongly single stepping - * into the interrupt handler. + * Mask all of DAIF while executing the instruction out-of-line, to keep things + * simple and avoid nesting exceptions. Interrupts do have to be disabled since + * the kprobe state is per-CPU and doesn't get migrated. */ static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb, struct pt_regs *regs) { kcb->saved_irqflag = regs->pstate & DAIF_MASK; - regs->pstate |= PSR_I_BIT; - /* Unmask PSTATE.D for enabling software step exceptions. */ - regs->pstate &= ~PSR_D_BIT; + regs->pstate |= DAIF_MASK; } static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb, @@ -219,10 +210,7 @@ static void __kprobes setup_singlestep(struct kprobe *p, slot = (unsigned long)p->ainsn.api.insn; set_ss_context(kcb, slot); /* mark pending ss */ - - /* IRQs and single stepping do not mix well. */ kprobes_save_local_irqflag(kcb, regs); - kernel_enable_single_step(regs); instruction_pointer_set(regs, slot); } else { /* insn simulation */ @@ -273,12 +261,8 @@ post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs) } /* call post handler */ kcb->kprobe_status = KPROBE_HIT_SSDONE; - if (cur->post_handler) { - /* post_handler can hit breakpoint and single step - * again, so we enable D-flag for recursive exception. - */ + if (cur->post_handler) cur->post_handler(cur, regs, 0); - } reset_current_kprobe(); } @@ -302,8 +286,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) if (!instruction_pointer(regs)) BUG(); - kernel_disable_single_step(); - if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); else @@ -365,10 +347,6 @@ static void __kprobes kprobe_handler(struct pt_regs *regs) * pre-handler and it returned non-zero, it will * modify the execution path and no need to single * stepping. Let's just reset current kprobe and exit. - * - * pre_handler can hit a breakpoint and can step thru - * before return, keep PSTATE D-flag enabled until - * pre_handler return back. */ if (!p->pre_handler || !p->pre_handler(p, regs)) { setup_singlestep(p, regs, kcb, 0); @@ -399,7 +377,7 @@ kprobe_ss_hit(struct kprobe_ctlblk *kcb, unsigned long addr) } static int __kprobes -kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) +kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned int esr) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); int retval; @@ -409,16 +387,15 @@ kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) if (retval == DBG_HOOK_HANDLED) { kprobes_restore_local_irqflag(kcb, regs); - kernel_disable_single_step(); - post_kprobe_handler(kcb, regs); } return retval; } -static struct step_hook kprobes_step_hook = { - .fn = kprobe_single_step_handler, +static struct break_hook kprobes_break_ss_hook = { + .imm = KPROBES_BRK_SS_IMM, + .fn = kprobe_breakpoint_ss_handler, }; static int __kprobes @@ -486,7 +463,7 @@ int __kprobes arch_trampoline_kprobe(struct kprobe *p) int __init arch_init_kprobes(void) { register_kernel_break_hook(&kprobes_break_hook); - register_kernel_step_hook(&kprobes_step_hook); + register_kernel_break_hook(&kprobes_break_ss_hook); return 0; } -- cgit v1.2.3 From 108aa503657ee2fe8aa071dc620d96372c252ecd Mon Sep 17 00:00:00 2001 From: Benjamin Gwin Date: Tue, 3 Nov 2020 12:11:06 -0800 Subject: arm64: kexec_file: try more regions if loading segments fails It's possible that the first region picked for the new kernel will make it impossible to fit the other segments in the required 32GB window, especially if we have a very large initrd. Instead of giving up, we can keep testing other regions for the kernel until we find one that works. Suggested-by: Ryan O'Leary Signed-off-by: Benjamin Gwin Link: https://lore.kernel.org/r/20201103201106.2397844-1-bgwin@google.com Signed-off-by: Will Deacon --- arch/arm64/kernel/kexec_image.c | 41 +++++++++++++++++++++++++--------- arch/arm64/kernel/machine_kexec_file.c | 9 +++++++- 2 files changed, 39 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c index af9987c154ca..66adee8b5fc8 100644 --- a/arch/arm64/kernel/kexec_image.c +++ b/arch/arm64/kernel/kexec_image.c @@ -43,7 +43,7 @@ static void *image_load(struct kimage *image, u64 flags, value; bool be_image, be_kernel; struct kexec_buf kbuf; - unsigned long text_offset; + unsigned long text_offset, kernel_segment_number; struct kexec_segment *kernel_segment; int ret; @@ -88,11 +88,37 @@ static void *image_load(struct kimage *image, /* Adjust kernel segment with TEXT_OFFSET */ kbuf.memsz += text_offset; - ret = kexec_add_buffer(&kbuf); - if (ret) + kernel_segment_number = image->nr_segments; + + /* + * The location of the kernel segment may make it impossible to satisfy + * the other segment requirements, so we try repeatedly to find a + * location that will work. + */ + while ((ret = kexec_add_buffer(&kbuf)) == 0) { + /* Try to load additional data */ + kernel_segment = &image->segment[kernel_segment_number]; + ret = load_other_segments(image, kernel_segment->mem, + kernel_segment->memsz, initrd, + initrd_len, cmdline); + if (!ret) + break; + + /* + * We couldn't find space for the other segments; erase the + * kernel segment and try the next available hole. + */ + image->nr_segments -= 1; + kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + } + + if (ret) { + pr_err("Could not find any suitable kernel location!"); return ERR_PTR(ret); + } - kernel_segment = &image->segment[image->nr_segments - 1]; + kernel_segment = &image->segment[kernel_segment_number]; kernel_segment->mem += text_offset; kernel_segment->memsz -= text_offset; image->start = kernel_segment->mem; @@ -101,12 +127,7 @@ static void *image_load(struct kimage *image, kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz); - /* Load additional data */ - ret = load_other_segments(image, - kernel_segment->mem, kernel_segment->memsz, - initrd, initrd_len, cmdline); - - return ERR_PTR(ret); + return 0; } #ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index 5b0e67b93cdc..03210f644790 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -240,6 +240,11 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) return ret; } +/* + * Tries to add the initrd and DTB to the image. If it is not possible to find + * valid locations, this function will undo changes to the image and return non + * zero. + */ int load_other_segments(struct kimage *image, unsigned long kernel_load_addr, unsigned long kernel_size, @@ -248,7 +253,8 @@ int load_other_segments(struct kimage *image, { struct kexec_buf kbuf; void *headers, *dtb = NULL; - unsigned long headers_sz, initrd_load_addr = 0, dtb_len; + unsigned long headers_sz, initrd_load_addr = 0, dtb_len, + orig_segments = image->nr_segments; int ret = 0; kbuf.image = image; @@ -334,6 +340,7 @@ int load_other_segments(struct kimage *image, return 0; out_err: + image->nr_segments = orig_segments; vfree(dtb); return ret; } -- cgit v1.2.3