diff options
Diffstat (limited to 'arch/arm64/kernel/probes')
| -rw-r--r-- | arch/arm64/kernel/probes/decode-insn.c | 48 | ||||
| -rw-r--r-- | arch/arm64/kernel/probes/kprobes.c | 36 |
2 files changed, 38 insertions, 46 deletions
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index 37e47a9d617e..d1731bf977ef 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -16,6 +16,7 @@ #include <linux/kernel.h> #include <linux/kprobes.h> #include <linux/module.h> +#include <linux/kallsyms.h> #include <asm/kprobes.h> #include <asm/insn.h> #include <asm/sections.h> @@ -122,7 +123,7 @@ arm_probe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) static bool __kprobes is_probed_address_atomic(kprobe_opcode_t *scan_start, kprobe_opcode_t *scan_end) { - while (scan_start > scan_end) { + while (scan_start >= scan_end) { /* * atomic region starts from exclusive load and ends with * exclusive store. @@ -142,33 +143,30 @@ arm_kprobe_decode_insn(kprobe_opcode_t *addr, struct arch_specific_insn *asi) { enum kprobe_insn decoded; kprobe_opcode_t insn = le32_to_cpu(*addr); - kprobe_opcode_t *scan_start = addr - 1; - kprobe_opcode_t *scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE; -#if defined(CONFIG_MODULES) && defined(MODULES_VADDR) - struct module *mod; -#endif - - if (addr >= (kprobe_opcode_t *)_text && - scan_end < (kprobe_opcode_t *)_text) - scan_end = (kprobe_opcode_t *)_text; -#if defined(CONFIG_MODULES) && defined(MODULES_VADDR) - else { - preempt_disable(); - mod = __module_address((unsigned long)addr); - if (mod && within_module_init((unsigned long)addr, mod) && - !within_module_init((unsigned long)scan_end, mod)) - scan_end = (kprobe_opcode_t *)mod->init_layout.base; - else if (mod && within_module_core((unsigned long)addr, mod) && - !within_module_core((unsigned long)scan_end, mod)) - scan_end = (kprobe_opcode_t *)mod->core_layout.base; - preempt_enable(); + kprobe_opcode_t *scan_end = NULL; + unsigned long size = 0, offset = 0; + + /* + * If there's a symbol defined in front of and near enough to + * the probe address assume it is the entry point to this + * code and use it to further limit how far back we search + * when determining if we're in an atomic sequence. If we could + * not find any symbol skip the atomic test altogether as we + * could otherwise end up searching irrelevant text/literals. + * KPROBES depends on KALLSYMS so this last case should never + * happen. + */ + if (kallsyms_lookup_size_offset((unsigned long) addr, &size, &offset)) { + if (offset < (MAX_ATOMIC_CONTEXT_SIZE*sizeof(kprobe_opcode_t))) + scan_end = addr - (offset / sizeof(kprobe_opcode_t)); + else + scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE; } -#endif decoded = arm_probe_decode_insn(insn, asi); - if (decoded == INSN_REJECTED || - is_probed_address_atomic(scan_start, scan_end)) - return INSN_REJECTED; + if (decoded != INSN_REJECTED && scan_end) + if (is_probed_address_atomic(addr - 1, scan_end)) + return INSN_REJECTED; return decoded; } diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index c6b0f40620d8..f5077ea7af6d 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -19,7 +19,7 @@ #include <linux/kasan.h> #include <linux/kernel.h> #include <linux/kprobes.h> -#include <linux/module.h> +#include <linux/extable.h> #include <linux/slab.h> #include <linux/stop_machine.h> #include <linux/stringify.h> @@ -31,7 +31,7 @@ #include <asm/insn.h> #include <asm/uaccess.h> #include <asm/irq.h> -#include <asm-generic/sections.h> +#include <asm/sections.h> #include "decode-insn.h" @@ -166,13 +166,18 @@ static void __kprobes set_current_kprobe(struct kprobe *p) } /* - * The D-flag (Debug mask) is set (masked) upon debug exception entry. - * Kprobes needs to clear (unmask) D-flag -ONLY- in case of recursive - * probe i.e. when probe hit from kprobe handler context upon - * executing the pre/post handlers. In this case we return with - * D-flag clear so that single-stepping can be carried-out. - * - * Leave D-flag set in all other cases. + * When PSTATE.D is set (masked), then software step exceptions can not be + * generated. + * SPSR's D bit shows the value of PSTATE.D immediately before the + * exception was taken. PSTATE.D is set while entering into any exception + * mode, however software clears it for any normal (none-debug-exception) + * mode in the exception entry. Therefore, when we are entering into kprobe + * breakpoint handler from any normal mode then SPSR.D bit is already + * cleared, however it is set when we are entering from any debug exception + * mode. + * Since we always need to generate single step exception after a kprobe + * breakpoint exception therefore we need to clear it unconditionally, when + * we become sure that the current breakpoint exception is for kprobe. */ static void __kprobes spsr_set_debug_flag(struct pt_regs *regs, int mask) @@ -245,10 +250,7 @@ static void __kprobes setup_singlestep(struct kprobe *p, set_ss_context(kcb, slot); /* mark pending ss */ - if (kcb->kprobe_status == KPROBE_REENTER) - spsr_set_debug_flag(regs, 0); - else - WARN_ON(regs->pstate & PSR_D_BIT); + spsr_set_debug_flag(regs, 0); /* IRQs and single stepping do not mix well. */ kprobes_save_local_irqflag(kcb, regs); @@ -333,8 +335,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr) BUG(); kernel_disable_single_step(); - if (kcb->kprobe_status == KPROBE_REENTER) - spsr_set_debug_flag(regs, 1); if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); @@ -457,9 +457,6 @@ kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) kprobes_restore_local_irqflag(kcb, regs); kernel_disable_single_step(); - if (kcb->kprobe_status == KPROBE_REENTER) - spsr_set_debug_flag(regs, 1); - post_kprobe_handler(kcb, regs); } @@ -543,9 +540,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) bool arch_within_kprobe_blacklist(unsigned long addr) { - extern char __idmap_text_start[], __idmap_text_end[]; - extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; - if ((addr >= (unsigned long)__kprobes_text_start && addr < (unsigned long)__kprobes_text_end) || (addr >= (unsigned long)__entry_text_start && |