--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -1117,6 +1117,9 @@ config MIPS_MSC
+@@ -1118,6 +1118,9 @@ config MIPS_MSC
config MIPS_NILE4
bool
+subsys_initcall(ar5312_gpio_init);
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -117,6 +117,7 @@ config ATH25
+@@ -118,6 +118,7 @@ config ATH25
select SYS_SUPPORTS_BIG_ENDIAN
select SYS_SUPPORTS_32BIT_KERNEL
select SYS_HAS_EARLY_PRINTK
#endif /* _ASM_R4KCACHE_H */
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
-@@ -358,6 +358,10 @@
+@@ -365,6 +365,10 @@
.macro RESTORE_SP_AND_RET
LONG_L sp, PT_R29(sp)
.set arch=r4000
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -206,6 +206,9 @@ config BCM63XX
+@@ -207,6 +207,9 @@ config BCM63XX
select SYNC_R4K
select DMA_NONCOHERENT
select IRQ_MIPS_CPU
--- /dev/null
+From: Matt Redfearn <matt.redfearn@imgtec.com>
+Date: Mon, 19 Dec 2016 14:20:56 +0000
+Subject: [PATCH] MIPS: Introduce irq_stack
+
+Allocate a per-cpu irq stack for use within interrupt handlers.
+
+Also add a utility function on_irq_stack to determine if a given stack
+pointer is within the irq stack for that cpu.
+
+Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
+---
+
+--- a/arch/mips/include/asm/irq.h
++++ b/arch/mips/include/asm/irq.h
+@@ -17,6 +17,18 @@
+
+ #include <irq.h>
+
++#define IRQ_STACK_SIZE THREAD_SIZE
++
++extern void *irq_stack[NR_CPUS];
++
++static inline bool on_irq_stack(int cpu, unsigned long sp)
++{
++ unsigned long low = (unsigned long)irq_stack[cpu];
++ unsigned long high = low + IRQ_STACK_SIZE;
++
++ return (low <= sp && sp <= high);
++}
++
+ #ifdef CONFIG_I8259
+ static inline int irq_canonicalize(int irq)
+ {
+--- a/arch/mips/kernel/asm-offsets.c
++++ b/arch/mips/kernel/asm-offsets.c
+@@ -101,6 +101,7 @@ void output_thread_info_defines(void)
+ OFFSET(TI_REGS, thread_info, regs);
+ DEFINE(_THREAD_SIZE, THREAD_SIZE);
+ DEFINE(_THREAD_MASK, THREAD_MASK);
++ DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
+ BLANK();
+ }
+
+--- a/arch/mips/kernel/irq.c
++++ b/arch/mips/kernel/irq.c
+@@ -25,6 +25,8 @@
+ #include <linux/atomic.h>
+ #include <asm/uaccess.h>
+
++void *irq_stack[NR_CPUS];
++
+ /*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+@@ -55,6 +57,15 @@ void __init init_IRQ(void)
+ irq_set_noprobe(i);
+
+ arch_init_irq();
++
++ for_each_possible_cpu(i) {
++ int irq_pages = IRQ_STACK_SIZE / PAGE_SIZE;
++ void *s = (void *)__get_free_pages(GFP_KERNEL, irq_pages);
++
++ irq_stack[i] = s;
++ pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
++ irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
++ }
+ }
+
+ #ifdef CONFIG_DEBUG_STACKOVERFLOW
--- /dev/null
+From: Matt Redfearn <matt.redfearn@imgtec.com>
+Date: Mon, 19 Dec 2016 14:20:57 +0000
+Subject: [PATCH] MIPS: Stack unwinding while on IRQ stack
+
+Within unwind stack, check if the stack pointer being unwound is within
+the CPU's irq_stack and if so use that page rather than the task's stack
+page.
+
+Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
+---
+
+--- a/arch/mips/kernel/process.c
++++ b/arch/mips/kernel/process.c
+@@ -32,6 +32,7 @@
+ #include <asm/cpu.h>
+ #include <asm/dsp.h>
+ #include <asm/fpu.h>
++#include <asm/irq.h>
+ #include <asm/msa.h>
+ #include <asm/pgtable.h>
+ #include <asm/mipsregs.h>
+@@ -507,7 +508,19 @@ EXPORT_SYMBOL(unwind_stack_by_address);
+ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+ unsigned long pc, unsigned long *ra)
+ {
+- unsigned long stack_page = (unsigned long)task_stack_page(task);
++ unsigned long stack_page = 0;
++ int cpu;
++
++ for_each_possible_cpu(cpu) {
++ if (on_irq_stack(cpu, *sp)) {
++ stack_page = (unsigned long)irq_stack[cpu];
++ break;
++ }
++ }
++
++ if (!stack_page)
++ stack_page = (unsigned long)task_stack_page(task);
++
+ return unwind_stack_by_address(stack_page, sp, pc, ra);
+ }
+ #endif
--- /dev/null
+From: Matt Redfearn <matt.redfearn@imgtec.com>
+Date: Mon, 19 Dec 2016 14:20:58 +0000
+Subject: [PATCH] MIPS: Only change $28 to thread_info if coming from user
+ mode
+
+The SAVE_SOME macro is used to save the execution context on all
+exceptions.
+If an exception occurs while executing user code, the stack is switched
+to the kernel's stack for the current task, and register $28 is switched
+to point to the current_thread_info, which is at the bottom of the stack
+region.
+If the exception occurs while executing kernel code, the stack is left,
+and this change ensures that register $28 is not updated. This is the
+correct behaviour when the kernel can be executing on the separate irq
+stack, because the thread_info will not be at the base of it.
+
+With this change, register $28 is only switched to it's kernel
+conventional usage of the currrent thread info pointer at the point at
+which execution enters kernel space. Doing it on every exception was
+redundant, but OK without an IRQ stack, but will be erroneous once that
+is introduced.
+
+Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
+Reviewed-by: Maciej W. Rozycki <macro@imgtec.com>
+---
+
+--- a/arch/mips/include/asm/stackframe.h
++++ b/arch/mips/include/asm/stackframe.h
+@@ -216,12 +216,19 @@
+ LONG_S $25, PT_R25(sp)
+ LONG_S $28, PT_R28(sp)
+ LONG_S $31, PT_R31(sp)
++
++ /* Set thread_info if we're coming from user mode */
++ mfc0 k0, CP0_STATUS
++ sll k0, 3 /* extract cu0 bit */
++ bltz k0, 9f
++
+ ori $28, sp, _THREAD_MASK
+ xori $28, _THREAD_MASK
+ #ifdef CONFIG_CPU_CAVIUM_OCTEON
+ .set mips64
+ pref 0, 0($28) /* Prefetch the current pointer */
+ #endif
++9:
+ .set pop
+ .endm
+
--- /dev/null
+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)
+
+ /*
--- /dev/null
+From: Matt Redfearn <matt.redfearn@imgtec.com>
+Date: Mon, 19 Dec 2016 14:21:00 +0000
+Subject: [PATCH] MIPS: Select HAVE_IRQ_EXIT_ON_IRQ_STACK
+
+Since do_IRQ is now invoked on a separate IRQ stack, we select
+HAVE_IRQ_EXIT_ON_IRQ_STACK so that softirq's may be invoked directly
+from irq_exit(), rather than requiring do_softirq_own_stack.
+
+Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
+---
+
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -9,6 +9,7 @@ config MIPS
+ select HAVE_CONTEXT_TRACKING
+ select HAVE_GENERIC_DMA_COHERENT
+ select HAVE_IDE
++ select HAVE_IRQ_EXIT_ON_IRQ_STACK
+ select HAVE_OPROFILE
+ select HAVE_PERF_EVENTS
+ select PERF_USE_VMALLOC
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -2752,10 +2752,10 @@ choice
+@@ -2753,10 +2753,10 @@ choice
the documented boot protocol using a device tree.
config MIPS_RAW_APPENDED_DTB
(e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
This is meant as a backward compatibility convenience for those
-@@ -2767,24 +2767,6 @@ choice
+@@ -2768,24 +2768,6 @@ choice
look like a DTB header after a reboot if no actual DTB is appended
to vmlinux.bin. Do not leave this option active in a production kernel
if you don't intend to always append a DTB.
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -1618,6 +1618,7 @@ config CPU_CAVIUM_OCTEON
+@@ -1619,6 +1619,7 @@ config CPU_CAVIUM_OCTEON
select USB_EHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN
select USB_OHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN
select MIPS_L1_CACHE_SHIFT_7
help
The Cavium Octeon processor is a highly integrated chip containing
many ethernet hardware widgets for networking tasks. The processor
-@@ -1913,6 +1914,9 @@ config MIPS_MALTA_PM
+@@ -1914,6 +1915,9 @@ config MIPS_MALTA_PM
bool
default y
---
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -1032,9 +1032,6 @@ config FW_ARC
+@@ -1033,9 +1033,6 @@ config FW_ARC
config ARCH_MAY_HAVE_PC_FDC
bool
config CEVT_BCM1480
bool
-@@ -2792,6 +2789,18 @@ choice
+@@ -2793,6 +2790,18 @@ choice
bool "Bootloader kernel arguments if available"
endchoice
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -1123,6 +1123,10 @@ config SYNC_R4K
+@@ -1124,6 +1124,10 @@ config SYNC_R4K
config MIPS_MACHINE
def_bool n
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -2724,6 +2724,20 @@ config MIPS_O32_FP64_SUPPORT
+@@ -2725,6 +2725,20 @@ config MIPS_O32_FP64_SUPPORT
If unsure, say N.
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -2220,6 +2220,12 @@ config MIPS_VPE_LOADER
+@@ -2221,6 +2221,12 @@ config MIPS_VPE_LOADER
Includes a loader for loading an elf relocatable object
onto another VPE and running it.
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -585,6 +585,8 @@ config RALINK
+@@ -586,6 +586,8 @@ config RALINK
select CLKDEV_LOOKUP
select ARCH_HAS_RESET_CONTROLLER
select RESET_CONTROLLER
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
-@@ -587,6 +587,9 @@ config RALINK
+@@ -588,6 +588,9 @@ config RALINK
select RESET_CONTROLLER
select PINCTRL
select PINCTRL_RT2880
projects / openwrt / openwrt.git / commitdiff