| From e49d38488515057dba8f0c2ba4cfde5be4a7281f Mon Sep 17 00:00:00 2001 |
| From: "Maciej W. Rozycki" <macro@imgtec.com> |
| Date: Tue, 17 May 2016 06:12:27 +0100 |
| Subject: MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC |
| |
| From: Maciej W. Rozycki <macro@imgtec.com> |
| |
| commit e49d38488515057dba8f0c2ba4cfde5be4a7281f upstream. |
| |
| 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: linux-mips@linux-mips.org |
| Patchwork: https://patchwork.linux-mips.org/patch/13271/ |
| Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/mips/include/asm/msa.h | 13 +++++++++++++ |
| arch/mips/kernel/traps.c | 6 +++--- |
| 2 files changed, 16 insertions(+), 3 deletions(-) |
| |
| --- a/arch/mips/include/asm/msa.h |
| +++ b/arch/mips/include/asm/msa.h |
| @@ -147,6 +147,19 @@ static inline void restore_msa(struct ta |
| _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) \ |
| --- a/arch/mips/kernel/traps.c |
| +++ b/arch/mips/kernel/traps.c |
| @@ -1249,7 +1249,7 @@ static int enable_restore_fp_context(int |
| 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); |
| } |
| @@ -1312,7 +1312,7 @@ static int enable_restore_fp_context(int |
| */ |
| 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; |
| } |
| @@ -1329,7 +1329,7 @@ static int enable_restore_fp_context(int |
| * 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); |