diff options
| author | Alex Sverdlin <alexander.sverdlin@nokia.com> | 2022-09-27 13:08:37 +0100 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2022-11-07 14:18:59 +0000 |
| commit | 4ab07fd3fbe6b6fe5f28e0e2987eb02bedc2b495 (patch) | |
| tree | bb709a7e4a21ba562f8b63652c2a5bd21ce4d6e2 | |
| parent | e66372ecb80dc5179c7abb880229c7452e813d15 (diff) | |
ARM: 9252/1: module: Teach unwinder about PLTs
"unwind: Index not found eef26358" warnings keep popping up on
CONFIG_ARM_MODULE_PLTS-enabled systems if the PC points to a PLT veneer.
Teach the unwinder how to deal with them, taking into account they don't
change state of the stack or register file except loading PC.
Link: https://lore.kernel.org/linux-arm-kernel/20200402153845.30985-1-kursad.oney@broadcom.com/
Tested-by: Kursad Oney <kursad.oney@broadcom.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
| -rw-r--r-- | arch/arm/include/asm/module.h | 5 | ||||
| -rw-r--r-- | arch/arm/kernel/module-plts.c | 14 | ||||
| -rw-r--r-- | arch/arm/kernel/unwind.c | 13 |
3 files changed, 31 insertions, 1 deletions
diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h index 5546c9751478..07c51a34f77d 100644 --- a/arch/arm/include/asm/module.h +++ b/arch/arm/include/asm/module.h @@ -37,6 +37,11 @@ struct mod_arch_specific { struct module; u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val); +#ifdef CONFIG_ARM_MODULE_PLTS +bool in_module_plt(unsigned long loc); +#else +static inline bool in_module_plt(unsigned long loc) { return false; } +#endif #ifdef CONFIG_THUMB2_KERNEL #define HAVE_ARCH_KALLSYMS_SYMBOL_VALUE diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c index 1fc309b41f94..af7c322ebed6 100644 --- a/arch/arm/kernel/module-plts.c +++ b/arch/arm/kernel/module-plts.c @@ -284,3 +284,17 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, mod->arch.core.plt->sh_size, mod->arch.init.plt->sh_size); return 0; } + +bool in_module_plt(unsigned long loc) +{ + struct module *mod; + bool ret; + + preempt_disable(); + mod = __module_text_address(loc); + ret = mod && (loc - (u32)mod->arch.core.plt_ent < mod->arch.core.plt_count * PLT_ENT_SIZE || + loc - (u32)mod->arch.init.plt_ent < mod->arch.init.plt_count * PLT_ENT_SIZE); + preempt_enable(); + + return ret; +} diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index a37ea6c772cd..53be7ea6181b 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/list.h> +#include <linux/module.h> #include <asm/stacktrace.h> #include <asm/traps.h> @@ -395,8 +396,18 @@ int unwind_frame(struct stackframe *frame) idx = unwind_find_idx(frame->pc); if (!idx) { - if (frame->pc && kernel_text_address(frame->pc)) + if (frame->pc && kernel_text_address(frame->pc)) { + if (in_module_plt(frame->pc) && frame->pc != frame->lr) { + /* + * Quoting Ard: Veneers only set PC using a + * PC+immediate LDR, and so they don't affect + * the state of the stack or the register file + */ + frame->pc = frame->lr; + return URC_OK; + } pr_warn("unwind: Index not found %08lx\n", frame->pc); + } return -URC_FAILURE; } |