From: Uwe Kleine-König Date: Mon, 16 Dec 2013 09:24:46 +0000 (+0100) Subject: ARM: make isa_mode macro more robust and fix for v7-M X-Git-Tag: v3.15-rc1~82^2^2~2^2~2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=3f18b1bf599d3d13cd81fdf6bf869c458772adfe;p=linux.git ARM: make isa_mode macro more robust and fix for v7-M The definition of isa_mode hardcodes the values to shift PSR_J_BIT and PSR_T_BIT to move them to bits 1 and 0 respectively. Instead use __ffs to calculate the shift from the #define already used for masking. This is relevant on v7-M as there PSR_T_BIT is 0x01000000 instead of 0x00000020 for V7-[AR] and earlier. Because of that isa_mode produced values >= 0x80000 which are unsuitable to index into isa_modes[4] there and so made __show_regs read from undefined memory which resulted in hangs and crashes. Moreover isa_mode is wrong for v7-M even after this robustness fix as there is no J-bit in the PSR register. So hardcode isa_mode to "Thumb" for v7-M. Signed-off-by: Uwe Kleine-König --- diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h index 04c99f36ff7f..627a03ebb987 100644 --- a/arch/arm/include/asm/ptrace.h +++ b/arch/arm/include/asm/ptrace.h @@ -27,9 +27,13 @@ struct pt_regs { #define thumb_mode(regs) (0) #endif +#ifndef CONFIG_CPU_V7M #define isa_mode(regs) \ - ((((regs)->ARM_cpsr & PSR_J_BIT) >> 23) | \ - (((regs)->ARM_cpsr & PSR_T_BIT) >> 5)) + ((((regs)->ARM_cpsr & PSR_J_BIT) >> (__ffs(PSR_J_BIT) - 1)) | \ + (((regs)->ARM_cpsr & PSR_T_BIT) >> (__ffs(PSR_T_BIT)))) +#else +#define isa_mode(regs) 1 /* Thumb */ +#endif #define processor_mode(regs) \ ((regs)->ARM_cpsr & MODE_MASK)