From d4cc510c61b050ef38e842a12feef71c56d7cf81 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Wed, 4 Mar 2009 11:48:46 +0100 Subject: [ARM] 5418/1: restore lr before leaving mcount MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gcc seems to expect that lr isn't clobbered by mcount, because for a function starting with: static int func(void) { void *ra = __builtin_return_address(0); printk(KERN_EMERG "__builtin_return_address(0) = %pS\n", ra) ... the following assembler is generated by gcc 4.3.2: 0: e1a0c00d mov ip, sp 4: e92dd810 push {r4, fp, ip, lr, pc} 8: e24cb004 sub fp, ip, #4 ; 0x4 c: ebfffffe bl 0 10: e59f0034 ldr r0, [pc, #52] 14: e1a0100e mov r1, lr 18: ebfffffe bl 0 Without this patch obviously __builtin_return_address(0) yields func+0x10 instead of the return address of the caller. Note this patch fixes a similar issue for the routines used with dynamic ftrace even though this isn't currently selectable for ARM. Cc: Abhishek Sagar Cc: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Uwe Kleine-König Signed-off-by: Russell King --- arch/arm/kernel/entry-common.S | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 49a6ba926c2..159d0416f27 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -111,6 +111,7 @@ ENTRY(mcount) .globl mcount_call mcount_call: bl ftrace_stub + ldr lr, [fp, #-4] @ restore lr ldmia sp!, {r0-r3, pc} ENTRY(ftrace_caller) @@ -122,6 +123,7 @@ ENTRY(ftrace_caller) .globl ftrace_call ftrace_call: bl ftrace_stub + ldr lr, [fp, #-4] @ restore lr ldmia sp!, {r0-r3, pc} #else @@ -133,6 +135,7 @@ ENTRY(mcount) adr r0, ftrace_stub cmp r0, r2 bne trace + ldr lr, [fp, #-4] @ restore lr ldmia sp!, {r0-r3, pc} trace: @@ -141,6 +144,7 @@ trace: sub r0, r0, #MCOUNT_INSN_SIZE mov lr, pc mov pc, r2 + mov lr, r1 @ restore lr ldmia sp!, {r0-r3, pc} #endif /* CONFIG_DYNAMIC_FTRACE */ -- cgit v1.2.3 From 446c92b2901bedb3725d29b4e73def8aba623ffc Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 12 Mar 2009 18:03:16 +0100 Subject: [ARM] 5421/1: ftrace: fix crash due to tracing of __naked functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a fix for the following crash observed in 2.6.29-rc3: http://lkml.org/lkml/2009/1/29/150 On ARM it doesn't make sense to trace a naked function because then mcount is called without stack and frame pointer being set up and there is no chance to restore the lr register to the value before mcount was called. Reported-by: Matthias Kaehlcke Tested-by: Matthias Kaehlcke Cc: Abhishek Sagar Cc: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Uwe Kleine-König Signed-off-by: Russell King --- arch/arm/kernel/fiq.c | 4 ++-- arch/arm/mm/copypage-feroceon.c | 2 +- arch/arm/mm/copypage-v3.c | 2 +- arch/arm/mm/copypage-v4mc.c | 2 +- arch/arm/mm/copypage-v4wb.c | 2 +- arch/arm/mm/copypage-v4wt.c | 2 +- arch/arm/mm/copypage-xsc3.c | 2 +- arch/arm/mm/copypage-xscale.c | 2 +- include/linux/compiler-gcc.h | 10 +++++++++- 9 files changed, 18 insertions(+), 10 deletions(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c index 36f81d96797..6ff7919613d 100644 --- a/arch/arm/kernel/fiq.c +++ b/arch/arm/kernel/fiq.c @@ -88,7 +88,7 @@ void set_fiq_handler(void *start, unsigned int length) * disable irqs for the duration. Note - these functions are almost * entirely coded in assembly. */ -void __attribute__((naked)) set_fiq_regs(struct pt_regs *regs) +void __naked set_fiq_regs(struct pt_regs *regs) { register unsigned long tmp; asm volatile ( @@ -106,7 +106,7 @@ void __attribute__((naked)) set_fiq_regs(struct pt_regs *regs) : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE)); } -void __attribute__((naked)) get_fiq_regs(struct pt_regs *regs) +void __naked get_fiq_regs(struct pt_regs *regs) { register unsigned long tmp; asm volatile ( diff --git a/arch/arm/mm/copypage-feroceon.c b/arch/arm/mm/copypage-feroceon.c index c3ba6a94da0..70997d5bee2 100644 --- a/arch/arm/mm/copypage-feroceon.c +++ b/arch/arm/mm/copypage-feroceon.c @@ -13,7 +13,7 @@ #include #include -static void __attribute__((naked)) +static void __naked feroceon_copy_user_page(void *kto, const void *kfrom) { asm("\ diff --git a/arch/arm/mm/copypage-v3.c b/arch/arm/mm/copypage-v3.c index 70ed96c8af8..de9c06854ad 100644 --- a/arch/arm/mm/copypage-v3.c +++ b/arch/arm/mm/copypage-v3.c @@ -15,7 +15,7 @@ * * FIXME: do we need to handle cache stuff... */ -static void __attribute__((naked)) +static void __naked v3_copy_user_page(void *kto, const void *kfrom) { asm("\n\ diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c index 1601698b980..7370a7142b0 100644 --- a/arch/arm/mm/copypage-v4mc.c +++ b/arch/arm/mm/copypage-v4mc.c @@ -44,7 +44,7 @@ static DEFINE_SPINLOCK(minicache_lock); * instruction. If your processor does not supply this, you have to write your * own copy_user_highpage that does the right thing. */ -static void __attribute__((naked)) +static void __naked mc_copy_user_page(void *from, void *to) { asm volatile( diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c index 3ec93dab765..9ab09841422 100644 --- a/arch/arm/mm/copypage-v4wb.c +++ b/arch/arm/mm/copypage-v4wb.c @@ -22,7 +22,7 @@ * instruction. If your processor does not supply this, you have to write your * own copy_user_highpage that does the right thing. */ -static void __attribute__((naked)) +static void __naked v4wb_copy_user_page(void *kto, const void *kfrom) { asm("\ diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c index 0f1188efae4..300efafd664 100644 --- a/arch/arm/mm/copypage-v4wt.c +++ b/arch/arm/mm/copypage-v4wt.c @@ -20,7 +20,7 @@ * dirty data in the cache. However, we do have to ensure that * subsequent reads are up to date. */ -static void __attribute__((naked)) +static void __naked v4wt_copy_user_page(void *kto, const void *kfrom) { asm("\ diff --git a/arch/arm/mm/copypage-xsc3.c b/arch/arm/mm/copypage-xsc3.c index 39a994542ca..bc4525f5ab2 100644 --- a/arch/arm/mm/copypage-xsc3.c +++ b/arch/arm/mm/copypage-xsc3.c @@ -29,7 +29,7 @@ * if we eventually end up using our copied page. * */ -static void __attribute__((naked)) +static void __naked xsc3_mc_copy_user_page(void *kto, const void *kfrom) { asm("\ diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c index d18f2397ee2..76824d3e966 100644 --- a/arch/arm/mm/copypage-xscale.c +++ b/arch/arm/mm/copypage-xscale.c @@ -42,7 +42,7 @@ static DEFINE_SPINLOCK(minicache_lock); * Dcache aliasing issue. The writes will be forwarded to the write buffer, * and merged as appropriate. */ -static void __attribute__((naked)) +static void __naked mc_copy_user_page(void *from, void *to) { /* diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 1514d534dee..a3ed7cb8ca3 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -52,7 +52,15 @@ #define __deprecated __attribute__((deprecated)) #define __packed __attribute__((packed)) #define __weak __attribute__((weak)) -#define __naked __attribute__((naked)) + +/* + * it doesn't make sense on ARM (currently the only user of __naked) to trace + * naked functions because then mcount is called without stack and frame pointer + * being set up and there is no chance to restore the lr register to the value + * before mcount was called. + */ +#define __naked __attribute__((naked)) notrace + #define __noreturn __attribute__((noreturn)) /* -- cgit v1.2.3