[PATCH v9 08/26] arm64: Make PMR part of task context
From: Julien Thierry <hidden>
Date: 2019-01-21 15:36:48
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), ptrace support, the rest · Maintainers:
Catalin Marinas, Will Deacon, Oleg Nesterov, Linus Torvalds
In order to replace PSR.I interrupt disabling/enabling with ICC_PMR_EL1 interrupt masking, ICC_PMR_EL1 needs to be saved/restored when taking/returning from an exception. This mimics the way hardware saves and restores PSR.I bit in spsr_el1 for exceptions and ERET. Add PMR to the registers to save in the pt_regs struct upon kernel entry, and restore it before ERET. Also, initialize it to a sane value when creating new tasks. Signed-off-by: Julien Thierry <redacted> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/include/asm/processor.h | 3 +++ arch/arm64/include/asm/ptrace.h | 14 +++++++++++--- arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/entry.S | 14 ++++++++++++++ arch/arm64/kernel/process.c | 6 ++++++ 5 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index f1a7ab1..5d9ce62 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h@@ -191,6 +191,9 @@ static inline void start_thread_common(struct pt_regs *regs, unsigned long pc) memset(regs, 0, sizeof(*regs)); forget_syscall(regs); regs->pc = pc; + + if (system_uses_irq_prio_masking()) + regs->pmr_save = GIC_PRIO_IRQON; } static inline void start_thread(struct pt_regs *regs, unsigned long pc,
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 05cf913..43e5df5 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h@@ -19,6 +19,8 @@ #ifndef __ASM_PTRACE_H #define __ASM_PTRACE_H +#include <asm/cpufeature.h> + #include <uapi/asm/ptrace.h> /* Current Exception Level values, as contained in CurrentEL */
@@ -179,7 +181,8 @@ struct pt_regs { #endif u64 orig_addr_limit; - u64 unused; // maintain 16 byte alignment + /* Only valid when ARM64_HAS_IRQ_PRIO_MASKING is enabled. */ + u64 pmr_save; u64 stackframe[2]; };
@@ -214,8 +217,13 @@ static inline void forget_syscall(struct pt_regs *regs) #define processor_mode(regs) \ ((regs)->pstate & PSR_MODE_MASK) -#define interrupts_enabled(regs) \ - (!((regs)->pstate & PSR_I_BIT)) +#define irqs_priority_unmasked(regs) \ + (system_uses_irq_prio_masking() ? \ + (regs)->pmr_save == GIC_PRIO_IRQON : \ + true) + +#define interrupts_enabled(regs) \ + (!((regs)->pstate & PSR_I_BIT) && irqs_priority_unmasked(regs)) #define fast_interrupts_enabled(regs) \ (!((regs)->pstate & PSR_F_BIT))
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 65b8afc..90ab2cf 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c@@ -81,6 +81,7 @@ int main(void) DEFINE(S_ORIG_X0, offsetof(struct pt_regs, orig_x0)); DEFINE(S_SYSCALLNO, offsetof(struct pt_regs, syscallno)); DEFINE(S_ORIG_ADDR_LIMIT, offsetof(struct pt_regs, orig_addr_limit)); + DEFINE(S_PMR_SAVE, offsetof(struct pt_regs, pmr_save)); DEFINE(S_STACKFRAME, offsetof(struct pt_regs, stackframe)); DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs)); BLANK();
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 0ec0c46..35a47f6 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S@@ -249,6 +249,12 @@ alternative_else_nop_endif msr sp_el0, tsk .endif + /* Save pmr */ +alternative_if ARM64_HAS_IRQ_PRIO_MASKING + mrs_s x20, SYS_ICC_PMR_EL1 + str x20, [sp, #S_PMR_SAVE] +alternative_else_nop_endif + /* * Registers that may be useful after this macro is invoked: *
@@ -269,6 +275,14 @@ alternative_else_nop_endif /* No need to restore UAO, it will be restored from SPSR_EL1 */ .endif + /* Restore pmr */ +alternative_if ARM64_HAS_IRQ_PRIO_MASKING + ldr x20, [sp, #S_PMR_SAVE] + msr_s SYS_ICC_PMR_EL1, x20 + /* Ensure priority change is seen by redistributor */ + dsb sy +alternative_else_nop_endif + ldp x21, x22, [sp, #S_PC] // load ELR, SPSR .if \el == 0 ct_user_enter
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index a0f985a..6d410fc 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c@@ -232,6 +232,9 @@ void __show_regs(struct pt_regs *regs) printk("sp : %016llx\n", sp); + if (system_uses_irq_prio_masking()) + printk("pmr_save: %08llx\n", regs->pmr_save); + i = top_reg; while (i >= 0) {
@@ -363,6 +366,9 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) childregs->pstate |= PSR_SSBS_BIT; + if (system_uses_irq_prio_masking()) + childregs->pmr_save = GIC_PRIO_IRQON; + p->thread.cpu_context.x19 = stack_start; p->thread.cpu_context.x20 = stk_sz; }
--
1.9.1
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