MIPS: Tracing: Fix 32-bit support with -mmcount-ra-address (3a2af2dc) · Commits · 戴 / test

For 32-bit kernel the -mmcount-ra-address option of gcc 4.5 emits one extra instruction before calling to _mcount so we need to use a different "b 1f" for it. Signed-off-by:

Wu Zhangjin <wuzhangjin@gmail.com> Cc: linux-mips <linux-mips@linux-mips.org> Cc: David Daney <david.s.daney@gmail.com> Patchwork: http://patchwork.linux-mips.org/patch/1228/ Signed-off-by:

Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/ftrace.c

+14 −2

Original line number	Diff line number	Diff line
		@@ -62,14 +62,26 @@ int ftrace_make_nop(struct module *mod,
		return -EFAULT;
		}

		#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
		/* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
		* addiu v1, v1, low_16bit_of_mcount
		* move at, ra
		* move $12, ra_address
		* jalr v1
		* sub sp, sp, 8
		* 1: offset = 5 instructions
		*/
		new = 0x10000005;
		#else
		/* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004)
		* addiu v1, v1, low_16bit_of_mcount
		* move at, ra
		* jalr v1
		* nop
		* 1f: (ip + 12)
		* nop \| move $12, ra_address \| sub sp, sp, 8
		* 1: offset = 4 instructions
		*/
		new = 0x10000004;
		#endif
		} else {
		/* record/calculate it for ftrace_make_call */
		if (jal_mcount == 0) {

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