[PATCH v28 4/9] arm64: kdump: implement machine_crash_shutdown()

[Catalin Marinas]

On Thu, Nov 24, 2016 at 06:58:05PM +0900, AKASHI Takahiro wrote:
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 04744dc..b5168e8 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -40,7 +40,47 @@
>  static inline void crash_setup_regs(struct pt_regs *newregs,
>  				    struct pt_regs *oldregs)
>  {
> -	/* Empty routine needed to avoid build errors. */
> +	if (oldregs) {
> +		memcpy(newregs, oldregs, sizeof(*newregs));
> +	} else {
> +		u64 tmp1, tmp2;
> +
> +		__asm__ __volatile__ (
> +			"stp	 x0,   x1, [%2, #16 *  0]\n"
> +			"stp	 x2,   x3, [%2, #16 *  1]\n"
> +			"stp	 x4,   x5, [%2, #16 *  2]\n"
> +			"stp	 x6,   x7, [%2, #16 *  3]\n"
> +			"stp	 x8,   x9, [%2, #16 *  4]\n"
> +			"stp	x10,  x11, [%2, #16 *  5]\n"
> +			"stp	x12,  x13, [%2, #16 *  6]\n"
> +			"stp	x14,  x15, [%2, #16 *  7]\n"
> +			"stp	x16,  x17, [%2, #16 *  8]\n"
> +			"stp	x18,  x19, [%2, #16 *  9]\n"
> +			"stp	x20,  x21, [%2, #16 * 10]\n"
> +			"stp	x22,  x23, [%2, #16 * 11]\n"
> +			"stp	x24,  x25, [%2, #16 * 12]\n"
> +			"stp	x26,  x27, [%2, #16 * 13]\n"
> +			"stp	x28,  x29, [%2, #16 * 14]\n"
> +			"mov	 %0,  sp\n"
> +			"stp	x30,  %0,  [%2, #16 * 15]\n"
> +
> +			"/* faked current PSTATE */\n"
> +			"mrs	 %0, CurrentEL\n"
> +			"mrs	 %1, SPSEL\n"
> +			"orr	 %0, %0, %1\n"
> +			"mrs	 %1, DAIF\n"
> +			"orr	 %0, %0, %1\n"
> +			"mrs	 %1, NZCV\n"
> +			"orr	 %0, %0, %1\n"
> +			/* pc */
> +			"adr	 %1, 1f\n"
> +		"1:\n"
> +			"stp	 %1, %0,   [%2, #16 * 16]\n"
> +			: "+r" (tmp1), "+r" (tmp2)
> +			: "r" (newregs)
> +			: "memory"

tmp1 and tmp2 are not input arguments here, so you should use the "=&"
modifier. With my compiler, I get warnings of these variables being used
uninitialised.

-- 
Catalin