MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC (e49d3848) · Commits · 戴 / test

Fix a build regression from commit ("MIPS: init upper 64b of vector registers when MSA is first used"): arch/mips/built-in.o: In function `enable_restore_fp_context': traps.c:(.text+0xbb90): undefined reference to `_init_msa_upper' traps.c:(.text+0xbb90): relocation truncated to fit: R_MIPS_26 against `_init_msa_upper' traps.c:(.text+0xbef0): undefined reference to `_init_msa_upper' traps.c:(.text+0xbef0): relocation truncated to fit: R_MIPS_26 against `_init_msa_upper' to !CONFIG_CPU_HAS_MSA configurations with older GCC versions, which are unable to figure out that calls to `_init_msa_upper' are indeed dead. Of the many ways to tackle this failure choose the approach we have already taken in `thread_msa_context_live'. [ralf@linux-mips.org: Drop patch segment to junk file.] Signed-off-by:

Maciej W. Rozycki <macro@imgtec.com> Cc: stable@vger.kernel.org # v3.16+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13271/ Signed-off-by:

Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/msa.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -147,6 +147,19 @@ static inline void restore_msa(struct task_struct *t)
		_restore_msa(t);
		}

		static inline void init_msa_upper(void)
		{
		/*
		* Check cpu_has_msa only if it's a constant. This will allow the
		* compiler to optimise out code for CPUs without MSA without adding
		* an extra redundant check for CPUs with MSA.
		*/
		if (__builtin_constant_p(cpu_has_msa) && !cpu_has_msa)
		return;

		_init_msa_upper();
		}

		#ifdef TOOLCHAIN_SUPPORTS_MSA

		#define __BUILD_MSA_CTL_REG(name, cs) \

arch/mips/kernel/traps.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1246,7 +1246,7 @@ static int enable_restore_fp_context(int msa)
		err = init_fpu();
		if (msa && !err) {
		enable_msa();
		_init_msa_upper();
		init_msa_upper();
		set_thread_flag(TIF_USEDMSA);
		set_thread_flag(TIF_MSA_CTX_LIVE);
		}
		@@ -1309,7 +1309,7 @@ static int enable_restore_fp_context(int msa)
		*/
		prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE);
		if (!prior_msa && was_fpu_owner) {
		_init_msa_upper();
		init_msa_upper();

		goto out;
		}
		@@ -1326,7 +1326,7 @@ static int enable_restore_fp_context(int msa)
		* of each vector register such that it cannot see data left
		* behind by another task.
		*/
		_init_msa_upper();
		init_msa_upper();
		} else {
		/* We need to restore the vector context. */
		restore_msa(current);

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