diff options
Diffstat (limited to 'target/linux/generic/patches-4.4/062-04-MIPS-Switch-to-the-irq_stack-in-interrupts.patch')
| -rw-r--r-- | target/linux/generic/patches-4.4/062-04-MIPS-Switch-to-the-irq_stack-in-interrupts.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/062-04-MIPS-Switch-to-the-irq_stack-in-interrupts.patch b/target/linux/generic/patches-4.4/062-04-MIPS-Switch-to-the-irq_stack-in-interrupts.patch new file mode 100644 index 0000000000..9bd2336974 --- /dev/null +++ b/target/linux/generic/patches-4.4/062-04-MIPS-Switch-to-the-irq_stack-in-interrupts.patch @@ -0,0 +1,116 @@ +From: Matt Redfearn <matt.redfearn@imgtec.com> +Date: Mon, 19 Dec 2016 14:20:59 +0000 +Subject: [PATCH] MIPS: Switch to the irq_stack in interrupts + +When enterring interrupt context via handle_int or except_vec_vi, switch +to the irq_stack of the current CPU if it is not already in use. + +The current stack pointer is masked with the thread size and compared to +the base or the irq stack. If it does not match then the stack pointer +is set to the top of that stack, otherwise this is a nested irq being +handled on the irq stack so the stack pointer should be left as it was. + +The in-use stack pointer is placed in the callee saved register s1. It +will be saved to the stack when plat_irq_dispatch is invoked and can be +restored once control returns here. + +Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> +--- + +--- a/arch/mips/kernel/genex.S ++++ b/arch/mips/kernel/genex.S +@@ -188,9 +188,44 @@ NESTED(handle_int, PT_SIZE, sp) + + LONG_L s0, TI_REGS($28) + LONG_S sp, TI_REGS($28) +- PTR_LA ra, ret_from_irq +- PTR_LA v0, plat_irq_dispatch +- jr v0 ++ ++ /* ++ * SAVE_ALL ensures we are using a valid kernel stack for the thread. ++ * Check if we are already using the IRQ stack. ++ */ ++ move s1, sp # Preserve the sp ++ ++ /* Get IRQ stack for this CPU */ ++ ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG ++#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) ++ lui k1, %hi(irq_stack) ++#else ++ lui k1, %highest(irq_stack) ++ daddiu k1, %higher(irq_stack) ++ dsll k1, 16 ++ daddiu k1, %hi(irq_stack) ++ dsll k1, 16 ++#endif ++ LONG_SRL k0, SMP_CPUID_PTRSHIFT ++ LONG_ADDU k1, k0 ++ LONG_L t0, %lo(irq_stack)(k1) ++ ++ # Check if already on IRQ stack ++ PTR_LI t1, ~(_THREAD_SIZE-1) ++ and t1, t1, sp ++ beq t0, t1, 2f ++ ++ /* Switch to IRQ stack */ ++ li t1, _IRQ_STACK_SIZE ++ PTR_ADD sp, t0, t1 ++ ++2: ++ jal plat_irq_dispatch ++ ++ /* Restore sp */ ++ move sp, s1 ++ ++ j ret_from_irq + #ifdef CONFIG_CPU_MICROMIPS + nop + #endif +@@ -263,8 +298,44 @@ NESTED(except_vec_vi_handler, 0, sp) + + LONG_L s0, TI_REGS($28) + LONG_S sp, TI_REGS($28) +- PTR_LA ra, ret_from_irq +- jr v0 ++ ++ /* ++ * SAVE_ALL ensures we are using a valid kernel stack for the thread. ++ * Check if we are already using the IRQ stack. ++ */ ++ move s1, sp # Preserve the sp ++ ++ /* Get IRQ stack for this CPU */ ++ ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG ++#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) ++ lui k1, %hi(irq_stack) ++#else ++ lui k1, %highest(irq_stack) ++ daddiu k1, %higher(irq_stack) ++ dsll k1, 16 ++ daddiu k1, %hi(irq_stack) ++ dsll k1, 16 ++#endif ++ LONG_SRL k0, SMP_CPUID_PTRSHIFT ++ LONG_ADDU k1, k0 ++ LONG_L t0, %lo(irq_stack)(k1) ++ ++ # Check if already on IRQ stack ++ PTR_LI t1, ~(_THREAD_SIZE-1) ++ and t1, t1, sp ++ beq t0, t1, 2f ++ ++ /* Switch to IRQ stack */ ++ li t1, _IRQ_STACK_SIZE ++ PTR_ADD sp, t0, t1 ++ ++2: ++ jal plat_irq_dispatch ++ ++ /* Restore sp */ ++ move sp, s1 ++ ++ j ret_from_irq + END(except_vec_vi_handler) + + /* |