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authorMarc Zyngier <marc.zyngier@arm.com>2019-07-22 14:53:09 +0100
committerWill Deacon <will@kernel.org>2019-07-22 15:24:16 +0100
commitcbdf8a189a66001c36007bf0f5c975d0376c5c3a (patch)
tree04692e85f7d27e7ff4c6c07aed2905a1d6b7112d /arch/arm64/include/asm/processor.h
parent4574b0b9abc83a3522b2e91c43b9f0c479855d3a (diff)
downloadlinux-cbdf8a189a66001c36007bf0f5c975d0376c5c3a.tar.bz2
arm64: Force SSBS on context switch
On a CPU that doesn't support SSBS, PSTATE[12] is RES0. In a system where only some of the CPUs implement SSBS, we end-up losing track of the SSBS bit across task migration. To address this issue, let's force the SSBS bit on context switch. Fixes: 8f04e8e6e29c ("arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3") Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> [will: inverted logic and added comments] Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm/processor.h')
-rw-r--r--arch/arm64/include/asm/processor.h14
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index fd5b1a4efc70..844e2964b0f5 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -193,6 +193,16 @@ static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
regs->pmr_save = GIC_PRIO_IRQON;
}
+static inline void set_ssbs_bit(struct pt_regs *regs)
+{
+ regs->pstate |= PSR_SSBS_BIT;
+}
+
+static inline void set_compat_ssbs_bit(struct pt_regs *regs)
+{
+ regs->pstate |= PSR_AA32_SSBS_BIT;
+}
+
static inline void start_thread(struct pt_regs *regs, unsigned long pc,
unsigned long sp)
{
@@ -200,7 +210,7 @@ static inline void start_thread(struct pt_regs *regs, unsigned long pc,
regs->pstate = PSR_MODE_EL0t;
if (arm64_get_ssbd_state() != ARM64_SSBD_FORCE_ENABLE)
- regs->pstate |= PSR_SSBS_BIT;
+ set_ssbs_bit(regs);
regs->sp = sp;
}
@@ -219,7 +229,7 @@ static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
#endif
if (arm64_get_ssbd_state() != ARM64_SSBD_FORCE_ENABLE)
- regs->pstate |= PSR_AA32_SSBS_BIT;
+ set_compat_ssbs_bit(regs);
regs->compat_sp = sp;
}