diff options
author | Stephen Boyd <sboyd@codeaurora.org> | 2015-10-02 11:15:13 -0700 |
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committer | Stephen Boyd <sboyd@codeaurora.org> | 2015-10-02 11:22:23 -0700 |
commit | 9f30a04d768f64280dc0c40b730746e82f298d88 (patch) | |
tree | e112853eb73627ed7b9a2ef8e4feab6685a0200e /arch/mips/include/asm/stackframe.h | |
parent | 9e294bf88a583825a413df408b9fe9e658fb93ac (diff) | |
parent | 7aba4f5201d1b7b3ddb0b03883d9edf69851ddad (diff) |
Merge branch 'for-4.3-rc/ti-clk-fixes' of https://github.com/t-kristo/linux-pm into clk-fixes
Pull fixes from Tero Kristo:
"A few TI clock driver fixes to pull against 4.3-rc"
* 'for-4.3-rc/ti-clk-fixes' of https://github.com/t-kristo/linux-pm: (3 commits)
clk: ti: dflt: fix enable_reg validity check
clk: ti: fix dual-registration of uart4_ick
clk: ti: clk-7xx: Remove hardwired ABE clock configuration
Diffstat (limited to 'arch/mips/include/asm/stackframe.h')
-rw-r--r-- | arch/mips/include/asm/stackframe.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h index 28d6d9364bd1f..a71da576883c8 100644 --- a/arch/mips/include/asm/stackframe.h +++ b/arch/mips/include/asm/stackframe.h @@ -152,6 +152,31 @@ .set noreorder bltz k0, 8f move k1, sp +#ifdef CONFIG_EVA + /* + * Flush interAptiv's Return Prediction Stack (RPS) by writing + * EntryHi. Toggling Config7.RPS is slower and less portable. + * + * The RPS isn't automatically flushed when exceptions are + * taken, which can result in kernel mode speculative accesses + * to user addresses if the RPS mispredicts. That's harmless + * when user and kernel share the same address space, but with + * EVA the same user segments may be unmapped to kernel mode, + * even containing sensitive MMIO regions or invalid memory. + * + * This can happen when the kernel sets the return address to + * ret_from_* and jr's to the exception handler, which looks + * more like a tail call than a function call. If nested calls + * don't evict the last user address in the RPS, it will + * mispredict the return and fetch from a user controlled + * address into the icache. + * + * More recent EVA-capable cores with MAAR to restrict + * speculative accesses aren't affected. + */ + MFC0 k0, CP0_ENTRYHI + MTC0 k0, CP0_ENTRYHI +#endif .set reorder /* Called from user mode, new stack. */ get_saved_sp |