From 50e51c13b3822d14ff6df4279423e4b7b2269bc3 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 10 Jan 2018 03:07:15 +1100 Subject: powerpc/64: Add macros for annotating the destination of rfid/hrfid The rfid/hrfid ((Hypervisor) Return From Interrupt) instruction is used for switching from the kernel to userspace, and from the hypervisor to the guest kernel. However it can and is also used for other transitions, eg. from real mode kernel code to virtual mode kernel code, and it's not always clear from the code what the destination context is. To make it clearer when reading the code, add macros which encode the expected destination context. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/exception-64s.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'arch/powerpc/include/asm/exception-64s.h') diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index b27205297e1d..1af427a3c74f 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -74,6 +74,35 @@ */ #define EX_R3 EX_DAR +/* Macros for annotating the expected destination of (h)rfid */ + +#define RFI_TO_KERNEL \ + rfid + +#define RFI_TO_USER \ + rfid + +#define RFI_TO_USER_OR_KERNEL \ + rfid + +#define RFI_TO_GUEST \ + rfid + +#define HRFI_TO_KERNEL \ + hrfid + +#define HRFI_TO_USER \ + hrfid + +#define HRFI_TO_USER_OR_KERNEL \ + hrfid + +#define HRFI_TO_GUEST \ + hrfid + +#define HRFI_TO_UNKNOWN \ + hrfid + #ifdef CONFIG_RELOCATABLE #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) \ mfspr r11,SPRN_##h##SRR0; /* save SRR0 */ \ -- cgit v1.2.3 From 222f20f140623ef6033491d0103ee0875fe87d35 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 10 Jan 2018 03:07:15 +1100 Subject: powerpc/64s: Simple RFI macro conversions This commit does simple conversions of rfi/rfid to the new macros that include the expected destination context. By simple we mean cases where there is a single well known destination context, and it's simply a matter of substituting the instruction for the appropriate macro. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/exception-64s.h | 4 ++-- arch/powerpc/kernel/entry_64.S | 14 +++++++++----- arch/powerpc/kernel/exceptions-64s.S | 24 ++++++++++++------------ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 9 ++++----- arch/powerpc/kvm/book3s_rmhandlers.S | 7 +++++-- arch/powerpc/kvm/book3s_segment.S | 4 ++-- 6 files changed, 34 insertions(+), 28 deletions(-) (limited to 'arch/powerpc/include/asm/exception-64s.h') diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 1af427a3c74f..dfc56daed98b 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -247,7 +247,7 @@ END_FTR_SECTION_NESTED(ftr,ftr,943) mtspr SPRN_##h##SRR0,r12; \ mfspr r12,SPRN_##h##SRR1; /* and SRR1 */ \ mtspr SPRN_##h##SRR1,r10; \ - h##rfid; \ + h##RFI_TO_KERNEL; \ b . /* prevent speculative execution */ #define EXCEPTION_PROLOG_PSERIES_1(label, h) \ __EXCEPTION_PROLOG_PSERIES_1(label, h) @@ -261,7 +261,7 @@ END_FTR_SECTION_NESTED(ftr,ftr,943) mtspr SPRN_##h##SRR0,r12; \ mfspr r12,SPRN_##h##SRR1; /* and SRR1 */ \ mtspr SPRN_##h##SRR1,r10; \ - h##rfid; \ + h##RFI_TO_KERNEL; \ b . /* prevent speculative execution */ #define EXCEPTION_PROLOG_PSERIES_1_NORI(label, h) \ diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 3320bcac7192..e68faa4d1b13 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -37,6 +37,11 @@ #include #include #include +#ifdef CONFIG_PPC_BOOK3S +#include +#else +#include +#endif /* * System calls. @@ -397,8 +402,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) mtmsrd r10, 1 mtspr SPRN_SRR0, r11 mtspr SPRN_SRR1, r12 - - rfid + RFI_TO_USER b . /* prevent speculative execution */ #endif _ASM_NOKPROBE_SYMBOL(system_call_common); @@ -1073,7 +1077,7 @@ __enter_rtas: mtspr SPRN_SRR0,r5 mtspr SPRN_SRR1,r6 - rfid + RFI_TO_KERNEL b . /* prevent speculative execution */ rtas_return_loc: @@ -1098,7 +1102,7 @@ rtas_return_loc: mtspr SPRN_SRR0,r3 mtspr SPRN_SRR1,r4 - rfid + RFI_TO_KERNEL b . /* prevent speculative execution */ _ASM_NOKPROBE_SYMBOL(__enter_rtas) _ASM_NOKPROBE_SYMBOL(rtas_return_loc) @@ -1171,7 +1175,7 @@ _GLOBAL(enter_prom) LOAD_REG_IMMEDIATE(r12, MSR_SF | MSR_ISF | MSR_LE) andc r11,r11,r12 mtsrr1 r11 - rfid + RFI_TO_KERNEL #endif /* CONFIG_PPC_BOOK3E */ 1: /* Return from OF */ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e441b469dc8f..5502b0147c4e 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -256,7 +256,7 @@ BEGIN_FTR_SECTION LOAD_HANDLER(r12, machine_check_handle_early) 1: mtspr SPRN_SRR0,r12 mtspr SPRN_SRR1,r11 - rfid + RFI_TO_KERNEL b . /* prevent speculative execution */ 2: /* Stack overflow. Stay on emergency stack and panic. @@ -445,7 +445,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early) li r3,MSR_ME andc r10,r10,r3 /* Turn off MSR_ME */ mtspr SPRN_SRR1,r10 - rfid + RFI_TO_KERNEL b . 2: /* @@ -463,7 +463,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early) */ bl machine_check_queue_event MACHINE_CHECK_HANDLER_WINDUP - rfid + RFI_TO_USER_OR_KERNEL 9: /* Deliver the machine check to host kernel in V mode. */ MACHINE_CHECK_HANDLER_WINDUP @@ -651,7 +651,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) mtspr SPRN_SRR0,r10 ld r10,PACAKMSR(r13) mtspr SPRN_SRR1,r10 - rfid + RFI_TO_KERNEL b . 8: std r3,PACA_EXSLB+EX_DAR(r13) @@ -662,7 +662,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) mtspr SPRN_SRR0,r10 ld r10,PACAKMSR(r13) mtspr SPRN_SRR1,r10 - rfid + RFI_TO_KERNEL b . EXC_COMMON_BEGIN(unrecov_slb) @@ -901,7 +901,7 @@ EXC_COMMON(trap_0b_common, 0xb00, unknown_exception) mtspr SPRN_SRR0,r10 ; \ ld r10,PACAKMSR(r13) ; \ mtspr SPRN_SRR1,r10 ; \ - rfid ; \ + RFI_TO_KERNEL ; \ b . ; /* prevent speculative execution */ #ifdef CONFIG_PPC_FAST_ENDIAN_SWITCH @@ -917,7 +917,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE) \ xori r12,r12,MSR_LE ; \ mtspr SPRN_SRR1,r12 ; \ mr r13,r9 ; \ - rfid ; /* return to userspace */ \ + RFI_TO_USER ; /* return to userspace */ \ b . ; /* prevent speculative execution */ #else #define SYSCALL_FASTENDIAN_TEST @@ -1063,7 +1063,7 @@ TRAMP_REAL_BEGIN(hmi_exception_early) mtcr r11 REST_GPR(11, r1) ld r1,GPR1(r1) - hrfid + HRFI_TO_USER_OR_KERNEL 1: mtcr r11 REST_GPR(11, r1) @@ -1314,7 +1314,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) ld r11,PACA_EXGEN+EX_R11(r13) ld r12,PACA_EXGEN+EX_R12(r13) ld r13,PACA_EXGEN+EX_R13(r13) - HRFID + HRFI_TO_UNKNOWN b . #endif @@ -1418,7 +1418,7 @@ masked_##_H##interrupt: \ ld r10,PACA_EXGEN+EX_R10(r13); \ ld r11,PACA_EXGEN+EX_R11(r13); \ /* returns to kernel where r13 must be set up, so don't restore it */ \ - ##_H##rfid; \ + ##_H##RFI_TO_KERNEL; \ b .; \ MASKED_DEC_HANDLER(_H) @@ -1441,7 +1441,7 @@ TRAMP_REAL_BEGIN(kvmppc_skip_interrupt) addi r13, r13, 4 mtspr SPRN_SRR0, r13 GET_SCRATCH0(r13) - rfid + RFI_TO_KERNEL b . TRAMP_REAL_BEGIN(kvmppc_skip_Hinterrupt) @@ -1453,7 +1453,7 @@ TRAMP_REAL_BEGIN(kvmppc_skip_Hinterrupt) addi r13, r13, 4 mtspr SPRN_HSRR0, r13 GET_SCRATCH0(r13) - hrfid + HRFI_TO_KERNEL b . #endif diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 2659844784b8..9c61f736c75b 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -79,7 +79,7 @@ _GLOBAL_TOC(kvmppc_hv_entry_trampoline) mtmsrd r0,1 /* clear RI in MSR */ mtsrr0 r5 mtsrr1 r6 - RFI + RFI_TO_KERNEL kvmppc_call_hv_entry: BEGIN_FTR_SECTION @@ -199,7 +199,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) mtmsrd r6, 1 /* Clear RI in MSR */ mtsrr0 r8 mtsrr1 r7 - RFI + RFI_TO_KERNEL /* Virtual-mode return */ .Lvirt_return: @@ -1167,8 +1167,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) ld r0, VCPU_GPR(R0)(r4) ld r4, VCPU_GPR(R4)(r4) - - hrfid + HRFI_TO_GUEST b . secondary_too_late: @@ -3320,7 +3319,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) ld r4, PACAKMSR(r13) mtspr SPRN_SRR0, r3 mtspr SPRN_SRR1, r4 - rfid + RFI_TO_KERNEL 9: addi r3, r1, STACK_FRAME_OVERHEAD bl kvmppc_bad_interrupt b 9b diff --git a/arch/powerpc/kvm/book3s_rmhandlers.S b/arch/powerpc/kvm/book3s_rmhandlers.S index 42a4b237df5f..34a5adeff084 100644 --- a/arch/powerpc/kvm/book3s_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_rmhandlers.S @@ -46,6 +46,9 @@ #define FUNC(name) name +#define RFI_TO_KERNEL RFI +#define RFI_TO_GUEST RFI + .macro INTERRUPT_TRAMPOLINE intno .global kvmppc_trampoline_\intno @@ -141,7 +144,7 @@ kvmppc_handler_skip_ins: GET_SCRATCH0(r13) /* And get back into the code */ - RFI + RFI_TO_KERNEL #endif /* @@ -164,6 +167,6 @@ _GLOBAL_TOC(kvmppc_entry_trampoline) ori r5, r5, MSR_EE mtsrr0 r7 mtsrr1 r6 - RFI + RFI_TO_KERNEL #include "book3s_segment.S" diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S index 2a2b96d53999..93a180ceefad 100644 --- a/arch/powerpc/kvm/book3s_segment.S +++ b/arch/powerpc/kvm/book3s_segment.S @@ -156,7 +156,7 @@ no_dcbz32_on: PPC_LL r9, SVCPU_R9(r3) PPC_LL r3, (SVCPU_R3)(r3) - RFI + RFI_TO_GUEST kvmppc_handler_trampoline_enter_end: @@ -407,5 +407,5 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) cmpwi r12, BOOK3S_INTERRUPT_DOORBELL beqa BOOK3S_INTERRUPT_DOORBELL - RFI + RFI_TO_KERNEL kvmppc_handler_trampoline_exit_end: -- cgit v1.2.3 From aa8a5e0062ac940f7659394f4817c948dc8c0667 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 10 Jan 2018 03:07:15 +1100 Subject: powerpc/64s: Add support for RFI flush of L1-D cache On some CPUs we can prevent the Meltdown vulnerability by flushing the L1-D cache on exit from kernel to user mode, and from hypervisor to guest. This is known to be the case on at least Power7, Power8 and Power9. At this time we do not know the status of the vulnerability on other CPUs such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale CPUs. As more information comes to light we can enable this, or other mechanisms on those CPUs. The vulnerability occurs when the load of an architecturally inaccessible memory region (eg. userspace load of kernel memory) is speculatively executed to the point where its result can influence the address of a subsequent speculatively executed load. In order for that to happen, the first load must hit in the L1, because before the load is sent to the L2 the permission check is performed. Therefore if no kernel addresses hit in the L1 the vulnerability can not occur. We can ensure that is the case by flushing the L1 whenever we return to userspace. Similarly for hypervisor vs guest. In order to flush the L1-D cache on exit, we add a section of nops at each (h)rfi location that returns to a lower privileged context, and patch that with some sequence. Newer firmwares are able to advertise to us that there is a special nop instruction that flushes the L1-D. If we do not see that advertised, we fall back to doing a displacement flush in software. For guest kernels we support migration between some CPU versions, and different CPUs may use different flush instructions. So that we are prepared to migrate to a machine with a different flush instruction activated, we may have to patch more than one flush instruction at boot if the hypervisor tells us to. In the end this patch is mostly the work of Nicholas Piggin and Michael Ellerman. However a cast of thousands contributed to analysis of the issue, earlier versions of the patch, back ports testing etc. Many thanks to all of them. Tested-by: Jon Masters Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/exception-64s.h | 40 ++++++++++++--- arch/powerpc/include/asm/feature-fixups.h | 13 +++++ arch/powerpc/include/asm/paca.h | 10 ++++ arch/powerpc/include/asm/setup.h | 13 +++++ arch/powerpc/kernel/asm-offsets.c | 5 ++ arch/powerpc/kernel/exceptions-64s.S | 84 +++++++++++++++++++++++++++++++ arch/powerpc/kernel/setup_64.c | 79 +++++++++++++++++++++++++++++ arch/powerpc/kernel/vmlinux.lds.S | 9 ++++ arch/powerpc/lib/feature-fixups.c | 41 +++++++++++++++ 9 files changed, 286 insertions(+), 8 deletions(-) (limited to 'arch/powerpc/include/asm/exception-64s.h') diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index dfc56daed98b..7197b179c1b1 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -74,34 +74,58 @@ */ #define EX_R3 EX_DAR -/* Macros for annotating the expected destination of (h)rfid */ +/* + * Macros for annotating the expected destination of (h)rfid + * + * The nop instructions allow us to insert one or more instructions to flush the + * L1-D cache when returning to userspace or a guest. + */ +#define RFI_FLUSH_SLOT \ + RFI_FLUSH_FIXUP_SECTION; \ + nop; \ + nop; \ + nop #define RFI_TO_KERNEL \ rfid #define RFI_TO_USER \ - rfid + RFI_FLUSH_SLOT; \ + rfid; \ + b rfi_flush_fallback #define RFI_TO_USER_OR_KERNEL \ - rfid + RFI_FLUSH_SLOT; \ + rfid; \ + b rfi_flush_fallback #define RFI_TO_GUEST \ - rfid + RFI_FLUSH_SLOT; \ + rfid; \ + b rfi_flush_fallback #define HRFI_TO_KERNEL \ hrfid #define HRFI_TO_USER \ - hrfid + RFI_FLUSH_SLOT; \ + hrfid; \ + b hrfi_flush_fallback #define HRFI_TO_USER_OR_KERNEL \ - hrfid + RFI_FLUSH_SLOT; \ + hrfid; \ + b hrfi_flush_fallback #define HRFI_TO_GUEST \ - hrfid + RFI_FLUSH_SLOT; \ + hrfid; \ + b hrfi_flush_fallback #define HRFI_TO_UNKNOWN \ - hrfid + RFI_FLUSH_SLOT; \ + hrfid; \ + b hrfi_flush_fallback #ifdef CONFIG_RELOCATABLE #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) \ diff --git a/arch/powerpc/include/asm/feature-fixups.h b/arch/powerpc/include/asm/feature-fixups.h index 8f88f771cc55..1e82eb3caabd 100644 --- a/arch/powerpc/include/asm/feature-fixups.h +++ b/arch/powerpc/include/asm/feature-fixups.h @@ -187,7 +187,20 @@ label##3: \ FTR_ENTRY_OFFSET label##1b-label##3b; \ .popsection; +#define RFI_FLUSH_FIXUP_SECTION \ +951: \ + .pushsection __rfi_flush_fixup,"a"; \ + .align 2; \ +952: \ + FTR_ENTRY_OFFSET 951b-952b; \ + .popsection; + + #ifndef __ASSEMBLY__ +#include + +extern long __start___rfi_flush_fixup, __stop___rfi_flush_fixup; + void apply_feature_fixups(void); void setup_feature_keys(void); #endif diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 3892db93b837..23ac7fc0af23 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -232,6 +232,16 @@ struct paca_struct { struct sibling_subcore_state *sibling_subcore_state; #endif #endif +#ifdef CONFIG_PPC_BOOK3S_64 + /* + * rfi fallback flush must be in its own cacheline to prevent + * other paca data leaking into the L1d + */ + u64 exrfi[EX_SIZE] __aligned(0x80); + void *rfi_flush_fallback_area; + u64 l1d_flush_congruence; + u64 l1d_flush_sets; +#endif }; extern void copy_mm_to_paca(struct mm_struct *mm); diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h index cf00ec26303a..469b7fdc9be4 100644 --- a/arch/powerpc/include/asm/setup.h +++ b/arch/powerpc/include/asm/setup.h @@ -39,6 +39,19 @@ static inline void pseries_big_endian_exceptions(void) {} static inline void pseries_little_endian_exceptions(void) {} #endif /* CONFIG_PPC_PSERIES */ +void rfi_flush_enable(bool enable); + +/* These are bit flags */ +enum l1d_flush_type { + L1D_FLUSH_NONE = 0x1, + L1D_FLUSH_FALLBACK = 0x2, + L1D_FLUSH_ORI = 0x4, + L1D_FLUSH_MTTRIG = 0x8, +}; + +void __init setup_rfi_flush(enum l1d_flush_type, bool enable); +void do_rfi_flush_fixups(enum l1d_flush_type types); + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_SETUP_H */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 6b958414b4e0..f390d57cf2e1 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -237,6 +237,11 @@ int main(void) OFFSET(PACA_NMI_EMERG_SP, paca_struct, nmi_emergency_sp); OFFSET(PACA_IN_MCE, paca_struct, in_mce); OFFSET(PACA_IN_NMI, paca_struct, in_nmi); + OFFSET(PACA_RFI_FLUSH_FALLBACK_AREA, paca_struct, rfi_flush_fallback_area); + OFFSET(PACA_EXRFI, paca_struct, exrfi); + OFFSET(PACA_L1D_FLUSH_CONGRUENCE, paca_struct, l1d_flush_congruence); + OFFSET(PACA_L1D_FLUSH_SETS, paca_struct, l1d_flush_sets); + #endif OFFSET(PACAHWCPUID, paca_struct, hw_cpu_id); OFFSET(PACAKEXECSTATE, paca_struct, kexec_state); diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index ed356194f09c..2dc10bf646b8 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1449,6 +1449,90 @@ masked_##_H##interrupt: \ b .; \ MASKED_DEC_HANDLER(_H) +TRAMP_REAL_BEGIN(rfi_flush_fallback) + SET_SCRATCH0(r13); + GET_PACA(r13); + std r9,PACA_EXRFI+EX_R9(r13) + std r10,PACA_EXRFI+EX_R10(r13) + std r11,PACA_EXRFI+EX_R11(r13) + std r12,PACA_EXRFI+EX_R12(r13) + std r8,PACA_EXRFI+EX_R13(r13) + mfctr r9 + ld r10,PACA_RFI_FLUSH_FALLBACK_AREA(r13) + ld r11,PACA_L1D_FLUSH_SETS(r13) + ld r12,PACA_L1D_FLUSH_CONGRUENCE(r13) + /* + * The load adresses are at staggered offsets within cachelines, + * which suits some pipelines better (on others it should not + * hurt). + */ + addi r12,r12,8 + mtctr r11 + DCBT_STOP_ALL_STREAM_IDS(r11) /* Stop prefetch streams */ + + /* order ld/st prior to dcbt stop all streams with flushing */ + sync +1: li r8,0 + .rept 8 /* 8-way set associative */ + ldx r11,r10,r8 + add r8,r8,r12 + xor r11,r11,r11 // Ensure r11 is 0 even if fallback area is not + add r8,r8,r11 // Add 0, this creates a dependency on the ldx + .endr + addi r10,r10,128 /* 128 byte cache line */ + bdnz 1b + + mtctr r9 + ld r9,PACA_EXRFI+EX_R9(r13) + ld r10,PACA_EXRFI+EX_R10(r13) + ld r11,PACA_EXRFI+EX_R11(r13) + ld r12,PACA_EXRFI+EX_R12(r13) + ld r8,PACA_EXRFI+EX_R13(r13) + GET_SCRATCH0(r13); + rfid + +TRAMP_REAL_BEGIN(hrfi_flush_fallback) + SET_SCRATCH0(r13); + GET_PACA(r13); + std r9,PACA_EXRFI+EX_R9(r13) + std r10,PACA_EXRFI+EX_R10(r13) + std r11,PACA_EXRFI+EX_R11(r13) + std r12,PACA_EXRFI+EX_R12(r13) + std r8,PACA_EXRFI+EX_R13(r13) + mfctr r9 + ld r10,PACA_RFI_FLUSH_FALLBACK_AREA(r13) + ld r11,PACA_L1D_FLUSH_SETS(r13) + ld r12,PACA_L1D_FLUSH_CONGRUENCE(r13) + /* + * The load adresses are at staggered offsets within cachelines, + * which suits some pipelines better (on others it should not + * hurt). + */ + addi r12,r12,8 + mtctr r11 + DCBT_STOP_ALL_STREAM_IDS(r11) /* Stop prefetch streams */ + + /* order ld/st prior to dcbt stop all streams with flushing */ + sync +1: li r8,0 + .rept 8 /* 8-way set associative */ + ldx r11,r10,r8 + add r8,r8,r12 + xor r11,r11,r11 // Ensure r11 is 0 even if fallback area is not + add r8,r8,r11 // Add 0, this creates a dependency on the ldx + .endr + addi r10,r10,128 /* 128 byte cache line */ + bdnz 1b + + mtctr r9 + ld r9,PACA_EXRFI+EX_R9(r13) + ld r10,PACA_EXRFI+EX_R10(r13) + ld r11,PACA_EXRFI+EX_R11(r13) + ld r12,PACA_EXRFI+EX_R12(r13) + ld r8,PACA_EXRFI+EX_R13(r13) + GET_SCRATCH0(r13); + hrfid + /* * Real mode exceptions actually use this too, but alternate * instruction code patches (which end up in the common .text area) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 8956a9856604..96163f4c3673 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -801,3 +801,82 @@ static int __init disable_hardlockup_detector(void) return 0; } early_initcall(disable_hardlockup_detector); + +#ifdef CONFIG_PPC_BOOK3S_64 +static enum l1d_flush_type enabled_flush_types; +static void *l1d_flush_fallback_area; +bool rfi_flush; + +static void do_nothing(void *unused) +{ + /* + * We don't need to do the flush explicitly, just enter+exit kernel is + * sufficient, the RFI exit handlers will do the right thing. + */ +} + +void rfi_flush_enable(bool enable) +{ + if (rfi_flush == enable) + return; + + if (enable) { + do_rfi_flush_fixups(enabled_flush_types); + on_each_cpu(do_nothing, NULL, 1); + } else + do_rfi_flush_fixups(L1D_FLUSH_NONE); + + rfi_flush = enable; +} + +static void init_fallback_flush(void) +{ + u64 l1d_size, limit; + int cpu; + + l1d_size = ppc64_caches.l1d.size; + limit = min(safe_stack_limit(), ppc64_rma_size); + + /* + * Align to L1d size, and size it at 2x L1d size, to catch possible + * hardware prefetch runoff. We don't have a recipe for load patterns to + * reliably avoid the prefetcher. + */ + l1d_flush_fallback_area = __va(memblock_alloc_base(l1d_size * 2, l1d_size, limit)); + memset(l1d_flush_fallback_area, 0, l1d_size * 2); + + for_each_possible_cpu(cpu) { + /* + * The fallback flush is currently coded for 8-way + * associativity. Different associativity is possible, but it + * will be treated as 8-way and may not evict the lines as + * effectively. + * + * 128 byte lines are mandatory. + */ + u64 c = l1d_size / 8; + + paca[cpu].rfi_flush_fallback_area = l1d_flush_fallback_area; + paca[cpu].l1d_flush_congruence = c; + paca[cpu].l1d_flush_sets = c / 128; + } +} + +void __init setup_rfi_flush(enum l1d_flush_type types, bool enable) +{ + if (types & L1D_FLUSH_FALLBACK) { + pr_info("rfi-flush: Using fallback displacement flush\n"); + init_fallback_flush(); + } + + if (types & L1D_FLUSH_ORI) + pr_info("rfi-flush: Using ori type flush\n"); + + if (types & L1D_FLUSH_MTTRIG) + pr_info("rfi-flush: Using mttrig type flush\n"); + + enabled_flush_types = types; + + rfi_flush_enable(enable); +} +#endif /* CONFIG_PPC_BOOK3S_64 */ diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 0494e1566ee2..307843d23682 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -132,6 +132,15 @@ SECTIONS /* Read-only data */ RO_DATA(PAGE_SIZE) +#ifdef CONFIG_PPC64 + . = ALIGN(8); + __rfi_flush_fixup : AT(ADDR(__rfi_flush_fixup) - LOAD_OFFSET) { + __start___rfi_flush_fixup = .; + *(__rfi_flush_fixup) + __stop___rfi_flush_fixup = .; + } +#endif + EXCEPTION_TABLE(0) NOTES :kernel :notes diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c index 41cf5ae273cf..a95ea007d654 100644 --- a/arch/powerpc/lib/feature-fixups.c +++ b/arch/powerpc/lib/feature-fixups.c @@ -116,6 +116,47 @@ void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end) } } +#ifdef CONFIG_PPC_BOOK3S_64 +void do_rfi_flush_fixups(enum l1d_flush_type types) +{ + unsigned int instrs[3], *dest; + long *start, *end; + int i; + + start = PTRRELOC(&__start___rfi_flush_fixup), + end = PTRRELOC(&__stop___rfi_flush_fixup); + + instrs[0] = 0x60000000; /* nop */ + instrs[1] = 0x60000000; /* nop */ + instrs[2] = 0x60000000; /* nop */ + + if (types & L1D_FLUSH_FALLBACK) + /* b .+16 to fallback flush */ + instrs[0] = 0x48000010; + + i = 0; + if (types & L1D_FLUSH_ORI) { + instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */ + instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/ + } + + if (types & L1D_FLUSH_MTTRIG) + instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */ + + for (i = 0; start < end; start++, i++) { + dest = (void *)start + *start; + + pr_devel("patching dest %lx\n", (unsigned long)dest); + + patch_instruction(dest, instrs[0]); + patch_instruction(dest + 1, instrs[1]); + patch_instruction(dest + 2, instrs[2]); + } + + printk(KERN_DEBUG "rfi-flush: patched %d locations\n", i); +} +#endif /* CONFIG_PPC_BOOK3S_64 */ + void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end) { long *start, *end; -- cgit v1.2.3