| Message ID | 1377639509-22778-18-git-send-email-ben.dooks@codethink.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 27, 2013 at 10:38:27PM +0100, Ben Dooks wrote: > Currently BUG() uses .word or .hword to create the necessary illegal > instructions. However if we are building BE8 then these get swapped > by the linker into different illegal instructions in the text. This > means that the BUG() macro does not get trapped properly. > > Change to using <asm/opcodes.h> to provide the necessary ARM instruction > building as we cannot rely on gcc/gas having the `.inst` instructions > which where added to try and resolve this issue (reported by Dave Martin > <Dave.Martin@arm.com>). Reviewed-by: Dave Martin <Dave.Martin@arm.com> > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/arm/include/asm/bug.h | 10 ++++++---- > arch/arm/kernel/traps.c | 8 +++++--- > 2 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h > index 7af5c6c..b274bde 100644 > --- a/arch/arm/include/asm/bug.h > +++ b/arch/arm/include/asm/bug.h > @@ -2,6 +2,8 @@ > #define _ASMARM_BUG_H > > #include <linux/linkage.h> > +#include <linux/types.h> > +#include <asm/opcodes.h> > > #ifdef CONFIG_BUG > > @@ -12,10 +14,10 @@ > */ > #ifdef CONFIG_THUMB2_KERNEL > #define BUG_INSTR_VALUE 0xde02 > -#define BUG_INSTR_TYPE ".hword " > +#define BUG_INSTR(__value) __inst_thumb16(__value) > #else > #define BUG_INSTR_VALUE 0xe7f001f2 > -#define BUG_INSTR_TYPE ".word " > +#define BUG_INSTR(__value) __inst_arm(__value) > #endif > > > @@ -33,7 +35,7 @@ > > #define __BUG(__file, __line, __value) \ > do { \ > - asm volatile("1:\t" BUG_INSTR_TYPE #__value "\n" \ > + asm volatile("1:\t" BUG_INSTR(__value) "\n" \ > ".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \ > "2:\t.asciz " #__file "\n" \ > ".popsection\n" \ > @@ -48,7 +50,7 @@ do { \ > > #define __BUG(__file, __line, __value) \ > do { \ > - asm volatile(BUG_INSTR_TYPE #__value); \ > + asm volatile(BUG_INSTR(__value) "\n"); \ > unreachable(); \ > } while (0) > #endif /* CONFIG_DEBUG_BUGVERBOSE */ > diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c > index 99bcd0e3..da070db 100644 > --- a/arch/arm/kernel/traps.c > +++ b/arch/arm/kernel/traps.c > @@ -342,15 +342,17 @@ void arm_notify_die(const char *str, struct pt_regs *regs, > int is_valid_bugaddr(unsigned long pc) > { > #ifdef CONFIG_THUMB2_KERNEL > - unsigned short bkpt; > + u16 bkpt; > + u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); > #else > - unsigned long bkpt; > + u32 bkpt; > + u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); > #endif > > if (probe_kernel_address((unsigned *)pc, bkpt)) > return 0; > > - return bkpt == BUG_INSTR_VALUE; > + return bkpt == insn; > } > > #endif > -- > 1.7.10.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h index 7af5c6c..b274bde 100644 --- a/arch/arm/include/asm/bug.h +++ b/arch/arm/include/asm/bug.h @@ -2,6 +2,8 @@ #define _ASMARM_BUG_H #include <linux/linkage.h> +#include <linux/types.h> +#include <asm/opcodes.h> #ifdef CONFIG_BUG @@ -12,10 +14,10 @@ */ #ifdef CONFIG_THUMB2_KERNEL #define BUG_INSTR_VALUE 0xde02 -#define BUG_INSTR_TYPE ".hword " +#define BUG_INSTR(__value) __inst_thumb16(__value) #else #define BUG_INSTR_VALUE 0xe7f001f2 -#define BUG_INSTR_TYPE ".word " +#define BUG_INSTR(__value) __inst_arm(__value) #endif @@ -33,7 +35,7 @@ #define __BUG(__file, __line, __value) \ do { \ - asm volatile("1:\t" BUG_INSTR_TYPE #__value "\n" \ + asm volatile("1:\t" BUG_INSTR(__value) "\n" \ ".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \ "2:\t.asciz " #__file "\n" \ ".popsection\n" \ @@ -48,7 +50,7 @@ do { \ #define __BUG(__file, __line, __value) \ do { \ - asm volatile(BUG_INSTR_TYPE #__value); \ + asm volatile(BUG_INSTR(__value) "\n"); \ unreachable(); \ } while (0) #endif /* CONFIG_DEBUG_BUGVERBOSE */ diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 99bcd0e3..da070db 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -342,15 +342,17 @@ void arm_notify_die(const char *str, struct pt_regs *regs, int is_valid_bugaddr(unsigned long pc) { #ifdef CONFIG_THUMB2_KERNEL - unsigned short bkpt; + u16 bkpt; + u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); #else - unsigned long bkpt; + u32 bkpt; + u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); #endif if (probe_kernel_address((unsigned *)pc, bkpt)) return 0; - return bkpt == BUG_INSTR_VALUE; + return bkpt == insn; } #endif
Currently BUG() uses .word or .hword to create the necessary illegal instructions. However if we are building BE8 then these get swapped by the linker into different illegal instructions in the text. This means that the BUG() macro does not get trapped properly. Change to using <asm/opcodes.h> to provide the necessary ARM instruction building as we cannot rely on gcc/gas having the `.inst` instructions which where added to try and resolve this issue (reported by Dave Martin <Dave.Martin@arm.com>). Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/include/asm/bug.h | 10 ++++++---- arch/arm/kernel/traps.c | 8 +++++--- 2 files changed, 11 insertions(+), 7 deletions(-)