diff options
| -rw-r--r-- | arch/powerpc/include/asm/switch_to.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 6 | ||||
| -rw-r--r-- | arch/powerpc/kernel/process.c | 8 | ||||
| -rw-r--r-- | tools/testing/selftests/powerpc/Makefile | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/powerpc/tm/Makefile | 15 | ||||
| -rw-r--r-- | tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 90 |
6 files changed, 114 insertions, 13 deletions
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 0e83e7d8c73..d2468eb1263 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -16,13 +16,15 @@ struct thread_struct; extern struct task_struct *_switch(struct thread_struct *prev, struct thread_struct *next); #ifdef CONFIG_PPC_BOOK3S_64 -static inline void save_tar(struct thread_struct *prev) +static inline void save_early_sprs(struct thread_struct *prev) { if (cpu_has_feature(CPU_FTR_ARCH_207S)) prev->tar = mfspr(SPRN_TAR); + if (cpu_has_feature(CPU_FTR_DSCR)) + prev->dscr = mfspr(SPRN_DSCR); } #else -static inline void save_tar(struct thread_struct *prev) {} +static inline void save_early_sprs(struct thread_struct *prev) {} #endif extern void enable_kernel_fp(void); diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 911d45366f5..6528c5e2cc4 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -428,12 +428,6 @@ BEGIN_FTR_SECTION std r24,THREAD_VRSAVE(r3) END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) #endif /* CONFIG_ALTIVEC */ -#ifdef CONFIG_PPC64 -BEGIN_FTR_SECTION - mfspr r25,SPRN_DSCR - std r25,THREAD_DSCR(r3) -END_FTR_SECTION_IFSET(CPU_FTR_DSCR) -#endif and. r0,r0,r22 beq+ 1f andc r22,r22,r0 diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 8a1edbe26b8..be99774d3f4 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -755,15 +755,15 @@ struct task_struct *__switch_to(struct task_struct *prev, WARN_ON(!irqs_disabled()); - /* Back up the TAR across context switches. + /* Back up the TAR and DSCR across context switches. * Note that the TAR is not available for use in the kernel. (To * provide this, the TAR should be backed up/restored on exception * entry/exit instead, and be in pt_regs. FIXME, this should be in * pt_regs anyway (for debug).) - * Save the TAR here before we do treclaim/trecheckpoint as these - * will change the TAR. + * Save the TAR and DSCR here before we do treclaim/trecheckpoint as + * these will change them. */ - save_tar(&prev->thread); + save_early_sprs(&prev->thread); __switch_to_tm(prev); diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile index b3dbe9ef1a4..54833a791a4 100644 --- a/tools/testing/selftests/powerpc/Makefile +++ b/tools/testing/selftests/powerpc/Makefile @@ -13,7 +13,7 @@ CFLAGS := -Wall -O2 -flto -Wall -Werror -DGIT_VERSION='"$(GIT_VERSION)"' -I$(CUR export CC CFLAGS -TARGETS = pmu copyloops mm +TARGETS = pmu copyloops mm tm endif diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile new file mode 100644 index 00000000000..51267f4184a --- /dev/null +++ b/tools/testing/selftests/powerpc/tm/Makefile @@ -0,0 +1,15 @@ +PROGS := tm-resched-dscr + +all: $(PROGS) + +$(PROGS): + +run_tests: all + @-for PROG in $(PROGS); do \ + ./$$PROG; \ + done; + +clean: + rm -f $(PROGS) *.o + +.PHONY: all run_tests clean diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c new file mode 100644 index 00000000000..ee98e3886af --- /dev/null +++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c @@ -0,0 +1,90 @@ +/* Test context switching to see if the DSCR SPR is correctly preserved + * when within a transaction. + * + * Note: We assume that the DSCR has been left at the default value (0) + * for all CPUs. + * + * Method: + * + * Set a value into the DSCR. + * + * Start a transaction, and suspend it (*). + * + * Hard loop checking to see if the transaction has become doomed. + * + * Now that we *may* have been preempted, record the DSCR and TEXASR SPRS. + * + * If the abort was because of a context switch, check the DSCR value. + * Otherwise, try again. + * + * (*) If the transaction is not suspended we can't see the problem because + * the transaction abort handler will restore the DSCR to it's checkpointed + * value before we regain control. + */ + +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> +#include <asm/tm.h> + +#define TBEGIN ".long 0x7C00051D ;" +#define TEND ".long 0x7C00055D ;" +#define TCHECK ".long 0x7C00059C ;" +#define TSUSPEND ".long 0x7C0005DD ;" +#define TRESUME ".long 0x7C2005DD ;" +#define SPRN_TEXASR 0x82 +#define SPRN_DSCR 0x03 + +int main(void) { + uint64_t rv, dscr1 = 1, dscr2, texasr; + + printf("Check DSCR TM context switch: "); + fflush(stdout); + for (;;) { + rv = 1; + asm __volatile__ ( + /* set a known value into the DSCR */ + "ld 3, %[dscr1];" + "mtspr %[sprn_dscr], 3;" + + /* start and suspend a transaction */ + TBEGIN + "beq 1f;" + TSUSPEND + + /* hard loop until the transaction becomes doomed */ + "2: ;" + TCHECK + "bc 4, 0, 2b;" + + /* record DSCR and TEXASR */ + "mfspr 3, %[sprn_dscr];" + "std 3, %[dscr2];" + "mfspr 3, %[sprn_texasr];" + "std 3, %[texasr];" + + TRESUME + TEND + "li %[rv], 0;" + "1: ;" + : [rv]"=r"(rv), [dscr2]"=m"(dscr2), [texasr]"=m"(texasr) + : [dscr1]"m"(dscr1) + , [sprn_dscr]"i"(SPRN_DSCR), [sprn_texasr]"i"(SPRN_TEXASR) + : "memory", "r3" + ); + assert(rv); /* make sure the transaction aborted */ + if ((texasr >> 56) != TM_CAUSE_RESCHED) { + putchar('.'); + fflush(stdout); + continue; + } + if (dscr2 != dscr1) { + printf(" FAIL\n"); + exit(EXIT_FAILURE); + } else { + printf(" OK\n"); + exit(EXIT_SUCCESS); + } + } +} |