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authorChristophe Leroy <christophe.leroy@csgroup.eu>2021-10-19 09:29:18 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2021-12-09 22:41:17 +1100
commit70428da94c7ad692d306747a04117543827292a7 (patch)
treea9c27bfdbaa5b4b79a93564f80ac31165f4ff560 /arch/powerpc/include/asm/processor.h
parent526d4a4c77aedf1b7df1133e5cced29c70232e6e (diff)
powerpc/32s: Save content of sr0 to avoid 'mfsr'
Calling 'mfsr' to get the content of segment registers is heavy, in addition it requires clearing of the 'reserved' bits. In order to avoid this operation, save it in mm context and in thread struct. The saved sr0 is the one used by kernel, this means that on locking entry it can be used as is. For unlocking, the only thing to do is to clear SR_NX. This improves null_syscall selftest by 12 cycles, ie 4%. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b02baf2ed8f09bad910dfaeeb7353b2ae6830525.1634627931.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/include/asm/processor.h')
-rw-r--r--arch/powerpc/include/asm/processor.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 978a80308466..fe1ef1d7523b 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -157,6 +157,7 @@ struct thread_struct {
#ifdef CONFIG_PPC_BOOK3S_32
unsigned long r0, r3, r4, r5, r6, r8, r9, r11;
unsigned long lr, ctr;
+ unsigned long sr0;
#endif
#endif /* CONFIG_PPC32 */
/* Debug Registers */
@@ -278,6 +279,12 @@ struct thread_struct {
#define SPEFSCR_INIT
#endif
+#ifdef CONFIG_PPC_BOOK3S_32
+#define SR0_INIT .sr0 = IS_ENABLED(CONFIG_PPC_KUEP) ? SR_NX : 0,
+#else
+#define SR0_INIT
+#endif
+
#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP)
#define INIT_THREAD { \
.ksp = INIT_SP, \
@@ -285,6 +292,7 @@ struct thread_struct {
.kuap = ~0UL, /* KUAP_NONE */ \
.fpexc_mode = MSR_FE0 | MSR_FE1, \
SPEFSCR_INIT \
+ SR0_INIT \
}
#elif defined(CONFIG_PPC32)
#define INIT_THREAD { \
@@ -292,6 +300,7 @@ struct thread_struct {
.pgdir = swapper_pg_dir, \
.fpexc_mode = MSR_FE0 | MSR_FE1, \
SPEFSCR_INIT \
+ SR0_INIT \
}
#else
#define INIT_THREAD { \