diff options
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 113 |
1 files changed, 111 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 9916d150b..73e461a3d 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -20,6 +20,7 @@ #include <linux/errno.h> #include <linux/err.h> +#include <linux/magic.h> #include <asm/unistd.h> #include <asm/processor.h> #include <asm/page.h> @@ -36,6 +37,7 @@ #include <asm/hw_irq.h> #include <asm/context_tracking.h> #include <asm/tm.h> +#include <asm/ppc-opcode.h> /* * System calls. @@ -508,6 +510,14 @@ BEGIN_FTR_SECTION ldarx r6,0,r1 END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS) +BEGIN_FTR_SECTION +/* + * A cp_abort (copy paste abort) here ensures that when context switching, a + * copy from one process can't leak into the paste of another. + */ + PPC_CP_ABORT +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) + #ifdef CONFIG_PPC_BOOK3S /* Cancel all explict user streams as they will have no use after context * switch and will stop the HW from creating streams itself @@ -519,7 +529,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS) std r6,PACACURRENT(r13) /* Set new 'current' */ ld r8,KSP(r4) /* new stack pointer */ -#ifdef CONFIG_PPC_BOOK3S +#ifdef CONFIG_PPC_STD_MMU_64 +BEGIN_MMU_FTR_SECTION + b 2f +END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX) BEGIN_FTR_SECTION clrrdi r6,r8,28 /* get its ESID */ clrrdi r9,r1,28 /* get current sp ESID */ @@ -565,7 +578,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT) slbmte r7,r0 isync 2: -#endif /* !CONFIG_PPC_BOOK3S */ +#endif /* CONFIG_PPC_STD_MMU_64 */ CURRENT_THREAD_INFO(r7, r8) /* base of new stack */ /* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE @@ -1248,6 +1261,9 @@ _GLOBAL(ftrace_caller) addi r3,r3,function_trace_op@toc@l ld r5,0(r3) +#ifdef CONFIG_LIVEPATCH + mr r14,r7 /* remember old NIP */ +#endif /* Calculate ip from nip-4 into r3 for call below */ subi r3, r7, MCOUNT_INSN_SIZE @@ -1272,6 +1288,9 @@ ftrace_call: /* Load ctr with the possibly modified NIP */ ld r3, _NIP(r1) mtctr r3 +#ifdef CONFIG_LIVEPATCH + cmpd r14,r3 /* has NIP been altered? */ +#endif /* Restore gprs */ REST_8GPRS(0,r1) @@ -1289,6 +1308,11 @@ ftrace_call: ld r0, LRSAVE(r1) mtlr r0 +#ifdef CONFIG_LIVEPATCH + /* Based on the cmpd above, if the NIP was altered handle livepatch */ + bne- livepatch_handler +#endif + #ifdef CONFIG_FUNCTION_GRAPH_TRACER stdu r1, -112(r1) .globl ftrace_graph_call @@ -1305,6 +1329,91 @@ _GLOBAL(ftrace_graph_stub) _GLOBAL(ftrace_stub) blr + +#ifdef CONFIG_LIVEPATCH + /* + * This function runs in the mcount context, between two functions. As + * such it can only clobber registers which are volatile and used in + * function linkage. + * + * We get here when a function A, calls another function B, but B has + * been live patched with a new function C. + * + * On entry: + * - we have no stack frame and can not allocate one + * - LR points back to the original caller (in A) + * - CTR holds the new NIP in C + * - r0 & r12 are free + * + * r0 can't be used as the base register for a DS-form load or store, so + * we temporarily shuffle r1 (stack pointer) into r0 and then put it back. + */ +livepatch_handler: + CURRENT_THREAD_INFO(r12, r1) + + /* Save stack pointer into r0 */ + mr r0, r1 + + /* Allocate 3 x 8 bytes */ + ld r1, TI_livepatch_sp(r12) + addi r1, r1, 24 + std r1, TI_livepatch_sp(r12) + + /* Save toc & real LR on livepatch stack */ + std r2, -24(r1) + mflr r12 + std r12, -16(r1) + + /* Store stack end marker */ + lis r12, STACK_END_MAGIC@h + ori r12, r12, STACK_END_MAGIC@l + std r12, -8(r1) + + /* Restore real stack pointer */ + mr r1, r0 + + /* Put ctr in r12 for global entry and branch there */ + mfctr r12 + bctrl + + /* + * Now we are returning from the patched function to the original + * caller A. We are free to use r0 and r12, and we can use r2 until we + * restore it. + */ + + CURRENT_THREAD_INFO(r12, r1) + + /* Save stack pointer into r0 */ + mr r0, r1 + + ld r1, TI_livepatch_sp(r12) + + /* Check stack marker hasn't been trashed */ + lis r2, STACK_END_MAGIC@h + ori r2, r2, STACK_END_MAGIC@l + ld r12, -8(r1) +1: tdne r12, r2 + EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0 + + /* Restore LR & toc from livepatch stack */ + ld r12, -16(r1) + mtlr r12 + ld r2, -24(r1) + + /* Pop livepatch stack frame */ + CURRENT_THREAD_INFO(r12, r0) + subi r1, r1, 24 + std r1, TI_livepatch_sp(r12) + + /* Restore real stack pointer */ + mr r1, r0 + + /* Return to original caller of live patched function */ + blr +#endif + + #else _GLOBAL_TOC(_mcount) /* Taken from output of objdump from lib64/glibc */ |