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authorMaciej W. Rozycki <macro@imgtec.com>2016-05-17 06:12:27 +0100
committerRalf Baechle <ralf@linux-mips.org>2016-05-17 11:02:45 +0200
commite49d38488515057dba8f0c2ba4cfde5be4a7281f (patch)
treecc141fabd9a4622c560e71beaaddffd0dd0ca5be /arch/mips
parent0868971a8dad52e726711a2a4b161ace9ed011fa (diff)
downloadlinux-e49d38488515057dba8f0c2ba4cfde5be4a7281f.tar.bz2
MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC
Fix a build regression from commit c9017757c532 ("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>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/include/asm/msa.h13
-rw-r--r--arch/mips/kernel/traps.c6
2 files changed, 16 insertions, 3 deletions
diff --git a/arch/mips/include/asm/msa.h b/arch/mips/include/asm/msa.h
index bbb85fe21642..6e4effa6f626 100644
--- a/arch/mips/include/asm/msa.h
+++ b/arch/mips/include/asm/msa.h
@@ -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) \
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 56f4161b98b9..4a1712b5abdf 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -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);