From 263e368a2f1f960db07d7524a4a3e7df951f1f72 Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Fri, 10 Jun 2011 20:29:04 +0100 Subject: [PATCH] ARM: kprobes: Add load_write_pc() This writes a value to PC which was obtained as the result of a LDR or LDM instruction. For ARMv5T and later this must perform interworking. Signed-off-by: Jon Medhurst Acked-by: Nicolas Pitre --- arch/arm/kernel/kprobes-common.c | 15 +++++++++++++++ arch/arm/kernel/kprobes.h | 24 ++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c index 3a3e765d209..86fdc4c4c2c 100644 --- a/arch/arm/kernel/kprobes-common.c +++ b/arch/arm/kernel/kprobes-common.c @@ -45,9 +45,24 @@ void __init find_str_pc_offset(void) #endif /* !find_str_pc_offset */ +#ifndef test_load_write_pc_interworking + +bool load_write_pc_interworks; + +void __init test_load_write_pc_interworking(void) +{ + int arch = cpu_architecture(); + BUG_ON(arch == CPU_ARCH_UNKNOWN); + load_write_pc_interworks = arch >= CPU_ARCH_ARMv5T; +} + +#endif /* !test_load_write_pc_interworking */ + + void __init arm_kprobe_decode_init(void) { find_str_pc_offset(); + test_load_write_pc_interworking(); } diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index 12627a376bf..5d6bf0d0a18 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -109,6 +109,30 @@ static inline void __kprobes bx_write_pc(long pcv, struct pt_regs *regs) regs->ARM_pc = pcv; } + +#if __LINUX_ARM_ARCH__ >= 6 + +/* Kernels built for >= ARMv6 should never run on <= ARMv5 hardware, so... */ +#define load_write_pc_interworks true +#define test_load_write_pc_interworking() + +#else /* __LINUX_ARM_ARCH__ < 6 */ + +/* We need run-time testing to determine if load_write_pc() should interwork. */ +extern bool load_write_pc_interworks; +void __init test_load_write_pc_interworking(void); + +#endif + +static inline void __kprobes load_write_pc(long pcv, struct pt_regs *regs) +{ + if (load_write_pc_interworks) + bx_write_pc(pcv, regs); + else + regs->ARM_pc = pcv; +} + + void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs); void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs); -- 2.39.5