diff options
| author | Anton Blanchard <anton@samba.org> | 2004-08-07 00:57:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-08-07 00:57:04 -0700 |
| commit | 3fe8bedc98380fdb5f1b9fb21a3758a96a360e71 (patch) | |
| tree | 03f7846862f0d250ab4f4541f1fc8a71671d0fab /arch | |
| parent | cc7919b79f539041f008aa41b1e8f127b951a009 (diff) | |
| download | history-3fe8bedc98380fdb5f1b9fb21a3758a96a360e71.tar.gz | |
[PATCH] ppc64: avoid speculative execution after rfid
Due to speculative execution, a CPU may execute some instructions after the
rfid. This makes profiles confusing, since profiling ticks could end up in
those instructions following the rfid that are never executed.
Add a branch to self after each rfid to avoid this.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/ppc64/kernel/entry.S | 5 | ||||
| -rw-r--r-- | arch/ppc64/kernel/head.S | 13 |
2 files changed, 16 insertions, 2 deletions
diff --git a/arch/ppc64/kernel/entry.S b/arch/ppc64/kernel/entry.S index 148bb78cedf4bf..2d48d24e7ab809 100644 --- a/arch/ppc64/kernel/entry.S +++ b/arch/ppc64/kernel/entry.S @@ -194,6 +194,7 @@ syscall_exit_trace_cont: mtspr SRR0,r7 mtspr SRR1,r8 rfid + b . /* prevent speculative execution */ syscall_enosys: li r3,-ENOSYS @@ -540,7 +541,7 @@ restore: ld r1,GPR1(r1) rfid - b . + b . /* prevent speculative execution */ /* Note: this must change if we start using the TIF_NOTIFY_RESUME bit */ do_work: @@ -684,6 +685,7 @@ _GLOBAL(enter_rtas) mtspr SRR0,r5 mtspr SRR1,r6 rfid + b . /* prevent speculative execution */ _STATIC(rtas_return_loc) /* relocation is off at this point */ @@ -704,6 +706,7 @@ _STATIC(rtas_return_loc) mtspr SRR0,r3 mtspr SRR1,r4 rfid + b . /* prevent speculative execution */ _STATIC(rtas_restore_regs) /* relocation is on at this point */ diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S index aefc7e6f00333b..3c2639b8c52019 100644 --- a/arch/ppc64/kernel/head.S +++ b/arch/ppc64/kernel/head.S @@ -221,7 +221,8 @@ exception_marker: mtspr SRR0,r12; \ mfspr r12,SRR1; /* and SRR1 */ \ mtspr SRR1,r10; \ - rfid + rfid; \ + b . /* prevent speculative execution */ /* * This is the start of the interrupt handlers for iSeries @@ -453,6 +454,7 @@ DataAccessSLB_Pseries: mtspr SRR1,r10 mfspr r3,DAR rfid + b . /* prevent speculative execution */ STD_EXCEPTION_PSERIES(0x400, InstructionAccess) @@ -479,6 +481,7 @@ InstructionAccessSLB_Pseries: mtspr SRR1,r10 mr r3,r11 /* SRR0 is faulting address */ rfid + b . /* prevent speculative execution */ STD_EXCEPTION_PSERIES(0x500, HardwareInterrupt) STD_EXCEPTION_PSERIES(0x600, Alignment) @@ -503,6 +506,7 @@ SystemCall_Pseries: mfspr r12,SRR1 mtspr SRR1,r10 rfid + b . /* prevent speculative execution */ STD_EXCEPTION_PSERIES(0xd00, SingleStep) STD_EXCEPTION_PSERIES(0xe00, Trap_0e) @@ -727,6 +731,7 @@ HardwareInterrupt_Iseries_masked: ld r12,PACA_EXGEN+EX_R12(r13) ld r13,PACA_EXGEN+EX_R13(r13) rfid + b . /* prevent speculative execution */ #endif /* @@ -867,6 +872,7 @@ fast_exception_return: REST_4GPRS(10, r1) ld r1,GPR1(r1) rfid + b . /* prevent speculative execution */ unrecov_fer: bl .save_nvgprs @@ -1146,6 +1152,7 @@ _GLOBAL(do_stab_bolted) ld r12,PACA_EXSLB+EX_R12(r13) ld r13,PACA_EXSLB+EX_R13(r13) rfid + b . /* prevent speculative execution */ /* * r13 points to the PACA, r9 contains the saved CR, @@ -1190,6 +1197,7 @@ _GLOBAL(do_slb_miss) ld r12,PACA_EXSLB+EX_R12(r13) ld r13,PACA_EXSLB+EX_R13(r13) rfid + b . /* prevent speculative execution */ unrecov_slb: EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB) @@ -1295,6 +1303,7 @@ _STATIC(mmu_off) mtspr SRR1,r3 sync rfid + b . /* prevent speculative execution */ _GLOBAL(__start_initialization_pSeries) mr r31,r3 /* save parameters */ mr r30,r4 @@ -1777,6 +1786,7 @@ _GLOBAL(__secondary_start) mtspr SRR0,r3 mtspr SRR1,r4 rfid + b . /* prevent speculative execution */ /* * Running with relocation on at this point. All we want to do is @@ -1940,6 +1950,7 @@ _STATIC(start_here_pSeries) mtspr SRR0,r3 mtspr SRR1,r4 rfid + b . /* prevent speculative execution */ #endif /* CONFIG_PPC_PSERIES */ /* This is where all platforms converge execution */ |