kernel: backport MIPS changes introducing a separate IRQ stack
Prevents crashes when IRQs arrive when the current kernel stack context already contains deeply nested function calls, e.g. when stacking lots of network devices on top of each other Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
parent
b02636fcb4
commit
1708644f19
17 changed files with 312 additions and 15 deletions
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@ -10,7 +10,7 @@
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -1117,6 +1117,9 @@ config MIPS_MSC
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@@ -1118,6 +1118,9 @@ config MIPS_MSC
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config MIPS_NILE4
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bool
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@ -202,7 +202,7 @@
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+subsys_initcall(ar5312_gpio_init);
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -117,6 +117,7 @@ config ATH25
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@@ -118,6 +118,7 @@ config ATH25
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select SYS_SUPPORTS_BIG_ENDIAN
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select SYS_SUPPORTS_32BIT_KERNEL
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select SYS_HAS_EARLY_PRINTK
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@ -260,7 +260,7 @@
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#endif /* _ASM_R4KCACHE_H */
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--- a/arch/mips/include/asm/stackframe.h
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+++ b/arch/mips/include/asm/stackframe.h
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@@ -358,6 +358,10 @@
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@@ -365,6 +365,10 @@
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.macro RESTORE_SP_AND_RET
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LONG_L sp, PT_R29(sp)
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.set arch=r4000
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@ -14,7 +14,7 @@ Signed-off-by: Jonas Gorski <jogo@openwrt.org>
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -206,6 +206,9 @@ config BCM63XX
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@@ -207,6 +207,9 @@ config BCM63XX
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select SYNC_R4K
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select DMA_NONCOHERENT
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select IRQ_MIPS_CPU
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@ -0,0 +1,70 @@
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From: Matt Redfearn <matt.redfearn@imgtec.com>
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Date: Mon, 19 Dec 2016 14:20:56 +0000
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Subject: [PATCH] MIPS: Introduce irq_stack
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Allocate a per-cpu irq stack for use within interrupt handlers.
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Also add a utility function on_irq_stack to determine if a given stack
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pointer is within the irq stack for that cpu.
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Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
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---
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--- a/arch/mips/include/asm/irq.h
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+++ b/arch/mips/include/asm/irq.h
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@@ -17,6 +17,18 @@
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#include <irq.h>
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+#define IRQ_STACK_SIZE THREAD_SIZE
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+
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+extern void *irq_stack[NR_CPUS];
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+
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+static inline bool on_irq_stack(int cpu, unsigned long sp)
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+{
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+ unsigned long low = (unsigned long)irq_stack[cpu];
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+ unsigned long high = low + IRQ_STACK_SIZE;
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+
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+ return (low <= sp && sp <= high);
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+}
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+
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#ifdef CONFIG_I8259
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static inline int irq_canonicalize(int irq)
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{
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--- a/arch/mips/kernel/asm-offsets.c
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+++ b/arch/mips/kernel/asm-offsets.c
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@@ -101,6 +101,7 @@ void output_thread_info_defines(void)
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OFFSET(TI_REGS, thread_info, regs);
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DEFINE(_THREAD_SIZE, THREAD_SIZE);
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DEFINE(_THREAD_MASK, THREAD_MASK);
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+ DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
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BLANK();
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}
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--- a/arch/mips/kernel/irq.c
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+++ b/arch/mips/kernel/irq.c
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@@ -25,6 +25,8 @@
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#include <linux/atomic.h>
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#include <asm/uaccess.h>
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+void *irq_stack[NR_CPUS];
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+
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/*
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* 'what should we do if we get a hw irq event on an illegal vector'.
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* each architecture has to answer this themselves.
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@@ -55,6 +57,15 @@ void __init init_IRQ(void)
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irq_set_noprobe(i);
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arch_init_irq();
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+
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+ for_each_possible_cpu(i) {
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+ int irq_pages = IRQ_STACK_SIZE / PAGE_SIZE;
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+ void *s = (void *)__get_free_pages(GFP_KERNEL, irq_pages);
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+
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+ irq_stack[i] = s;
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+ pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
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+ irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
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+ }
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}
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#ifdef CONFIG_DEBUG_STACKOVERFLOW
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@ -0,0 +1,42 @@
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From: Matt Redfearn <matt.redfearn@imgtec.com>
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Date: Mon, 19 Dec 2016 14:20:57 +0000
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Subject: [PATCH] MIPS: Stack unwinding while on IRQ stack
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Within unwind stack, check if the stack pointer being unwound is within
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the CPU's irq_stack and if so use that page rather than the task's stack
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page.
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Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
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---
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--- a/arch/mips/kernel/process.c
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+++ b/arch/mips/kernel/process.c
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@@ -32,6 +32,7 @@
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#include <asm/cpu.h>
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#include <asm/dsp.h>
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#include <asm/fpu.h>
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+#include <asm/irq.h>
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#include <asm/msa.h>
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#include <asm/pgtable.h>
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#include <asm/mipsregs.h>
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@@ -507,7 +508,19 @@ EXPORT_SYMBOL(unwind_stack_by_address);
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unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
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unsigned long pc, unsigned long *ra)
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{
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- unsigned long stack_page = (unsigned long)task_stack_page(task);
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+ unsigned long stack_page = 0;
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+ int cpu;
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+
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+ for_each_possible_cpu(cpu) {
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+ if (on_irq_stack(cpu, *sp)) {
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+ stack_page = (unsigned long)irq_stack[cpu];
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+ break;
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+ }
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+ }
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+
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+ if (!stack_page)
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+ stack_page = (unsigned long)task_stack_page(task);
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+
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return unwind_stack_by_address(stack_page, sp, pc, ra);
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}
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#endif
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@ -0,0 +1,48 @@
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From: Matt Redfearn <matt.redfearn@imgtec.com>
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Date: Mon, 19 Dec 2016 14:20:58 +0000
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Subject: [PATCH] MIPS: Only change $28 to thread_info if coming from user
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mode
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The SAVE_SOME macro is used to save the execution context on all
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exceptions.
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If an exception occurs while executing user code, the stack is switched
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to the kernel's stack for the current task, and register $28 is switched
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to point to the current_thread_info, which is at the bottom of the stack
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region.
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If the exception occurs while executing kernel code, the stack is left,
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and this change ensures that register $28 is not updated. This is the
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correct behaviour when the kernel can be executing on the separate irq
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stack, because the thread_info will not be at the base of it.
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With this change, register $28 is only switched to it's kernel
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conventional usage of the currrent thread info pointer at the point at
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which execution enters kernel space. Doing it on every exception was
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redundant, but OK without an IRQ stack, but will be erroneous once that
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is introduced.
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Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
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Reviewed-by: Maciej W. Rozycki <macro@imgtec.com>
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---
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--- a/arch/mips/include/asm/stackframe.h
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+++ b/arch/mips/include/asm/stackframe.h
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@@ -216,12 +216,19 @@
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LONG_S $25, PT_R25(sp)
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LONG_S $28, PT_R28(sp)
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LONG_S $31, PT_R31(sp)
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+
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+ /* Set thread_info if we're coming from user mode */
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+ mfc0 k0, CP0_STATUS
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+ sll k0, 3 /* extract cu0 bit */
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+ bltz k0, 9f
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+
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ori $28, sp, _THREAD_MASK
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xori $28, _THREAD_MASK
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#ifdef CONFIG_CPU_CAVIUM_OCTEON
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.set mips64
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pref 0, 0($28) /* Prefetch the current pointer */
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#endif
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+9:
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.set pop
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.endm
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@ -0,0 +1,116 @@
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From: Matt Redfearn <matt.redfearn@imgtec.com>
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Date: Mon, 19 Dec 2016 14:20:59 +0000
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Subject: [PATCH] MIPS: Switch to the irq_stack in interrupts
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When enterring interrupt context via handle_int or except_vec_vi, switch
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to the irq_stack of the current CPU if it is not already in use.
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The current stack pointer is masked with the thread size and compared to
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the base or the irq stack. If it does not match then the stack pointer
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is set to the top of that stack, otherwise this is a nested irq being
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handled on the irq stack so the stack pointer should be left as it was.
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The in-use stack pointer is placed in the callee saved register s1. It
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will be saved to the stack when plat_irq_dispatch is invoked and can be
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restored once control returns here.
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Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
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---
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--- a/arch/mips/kernel/genex.S
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+++ b/arch/mips/kernel/genex.S
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@@ -188,9 +188,44 @@ NESTED(handle_int, PT_SIZE, sp)
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LONG_L s0, TI_REGS($28)
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LONG_S sp, TI_REGS($28)
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- PTR_LA ra, ret_from_irq
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- PTR_LA v0, plat_irq_dispatch
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- jr v0
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+
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+ /*
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+ * SAVE_ALL ensures we are using a valid kernel stack for the thread.
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+ * Check if we are already using the IRQ stack.
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+ */
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+ move s1, sp # Preserve the sp
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+
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+ /* Get IRQ stack for this CPU */
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+ ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG
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+#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
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+ lui k1, %hi(irq_stack)
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+#else
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+ lui k1, %highest(irq_stack)
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+ daddiu k1, %higher(irq_stack)
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+ dsll k1, 16
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+ daddiu k1, %hi(irq_stack)
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+ dsll k1, 16
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+#endif
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+ LONG_SRL k0, SMP_CPUID_PTRSHIFT
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+ LONG_ADDU k1, k0
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+ LONG_L t0, %lo(irq_stack)(k1)
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+
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+ # Check if already on IRQ stack
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+ PTR_LI t1, ~(_THREAD_SIZE-1)
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+ and t1, t1, sp
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+ beq t0, t1, 2f
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+
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+ /* Switch to IRQ stack */
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+ li t1, _IRQ_STACK_SIZE
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+ PTR_ADD sp, t0, t1
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+
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+2:
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+ jal plat_irq_dispatch
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+
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+ /* Restore sp */
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+ move sp, s1
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+
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+ j ret_from_irq
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#ifdef CONFIG_CPU_MICROMIPS
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nop
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#endif
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@@ -263,8 +298,44 @@ NESTED(except_vec_vi_handler, 0, sp)
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LONG_L s0, TI_REGS($28)
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LONG_S sp, TI_REGS($28)
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- PTR_LA ra, ret_from_irq
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- jr v0
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+
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+ /*
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+ * SAVE_ALL ensures we are using a valid kernel stack for the thread.
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+ * Check if we are already using the IRQ stack.
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+ */
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+ move s1, sp # Preserve the sp
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+
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+ /* Get IRQ stack for this CPU */
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+ ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG
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+#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
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+ lui k1, %hi(irq_stack)
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+#else
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+ lui k1, %highest(irq_stack)
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+ daddiu k1, %higher(irq_stack)
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+ dsll k1, 16
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+ daddiu k1, %hi(irq_stack)
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+ dsll k1, 16
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+#endif
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+ LONG_SRL k0, SMP_CPUID_PTRSHIFT
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+ LONG_ADDU k1, k0
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+ LONG_L t0, %lo(irq_stack)(k1)
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+
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+ # Check if already on IRQ stack
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+ PTR_LI t1, ~(_THREAD_SIZE-1)
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+ and t1, t1, sp
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+ beq t0, t1, 2f
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+
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+ /* Switch to IRQ stack */
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+ li t1, _IRQ_STACK_SIZE
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+ PTR_ADD sp, t0, t1
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+
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+2:
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+ jal plat_irq_dispatch
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+
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+ /* Restore sp */
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+ move sp, s1
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+
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+ j ret_from_irq
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END(except_vec_vi_handler)
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/*
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@ -0,0 +1,21 @@
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From: Matt Redfearn <matt.redfearn@imgtec.com>
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Date: Mon, 19 Dec 2016 14:21:00 +0000
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Subject: [PATCH] MIPS: Select HAVE_IRQ_EXIT_ON_IRQ_STACK
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Since do_IRQ is now invoked on a separate IRQ stack, we select
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HAVE_IRQ_EXIT_ON_IRQ_STACK so that softirq's may be invoked directly
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from irq_exit(), rather than requiring do_softirq_own_stack.
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Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
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---
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -9,6 +9,7 @@ config MIPS
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select HAVE_CONTEXT_TRACKING
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select HAVE_GENERIC_DMA_COHERENT
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select HAVE_IDE
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+ select HAVE_IRQ_EXIT_ON_IRQ_STACK
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select HAVE_OPROFILE
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select HAVE_PERF_EVENTS
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select PERF_USE_VMALLOC
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@ -27,7 +27,7 @@ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -2752,10 +2752,10 @@ choice
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@@ -2753,10 +2753,10 @@ choice
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the documented boot protocol using a device tree.
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config MIPS_RAW_APPENDED_DTB
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@ -40,7 +40,7 @@ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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(e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
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This is meant as a backward compatibility convenience for those
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@@ -2767,24 +2767,6 @@ choice
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@@ -2768,24 +2768,6 @@ choice
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look like a DTB header after a reboot if no actual DTB is appended
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to vmlinux.bin. Do not leave this option active in a production kernel
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if you don't intend to always append a DTB.
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|
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@ -19,7 +19,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -1618,6 +1618,7 @@ config CPU_CAVIUM_OCTEON
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@@ -1619,6 +1619,7 @@ config CPU_CAVIUM_OCTEON
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select USB_EHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN
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select USB_OHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN
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select MIPS_L1_CACHE_SHIFT_7
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@ -27,7 +27,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
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help
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The Cavium Octeon processor is a highly integrated chip containing
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many ethernet hardware widgets for networking tasks. The processor
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@@ -1913,6 +1914,9 @@ config MIPS_MALTA_PM
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@@ -1914,6 +1915,9 @@ config MIPS_MALTA_PM
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bool
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default y
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|
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@ -8,7 +8,7 @@ Acked-by: Rob Landley <rob@landley.net>
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---
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -1032,9 +1032,6 @@ config FW_ARC
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@@ -1033,9 +1033,6 @@ config FW_ARC
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config ARCH_MAY_HAVE_PC_FDC
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bool
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@ -18,7 +18,7 @@ Acked-by: Rob Landley <rob@landley.net>
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config CEVT_BCM1480
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bool
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@@ -2792,6 +2789,18 @@ choice
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@@ -2793,6 +2790,18 @@ choice
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bool "Bootloader kernel arguments if available"
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endchoice
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|
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@ -1,6 +1,6 @@
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -1123,6 +1123,10 @@ config SYNC_R4K
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@@ -1124,6 +1124,10 @@ config SYNC_R4K
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config MIPS_MACHINE
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def_bool n
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|
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|
@ -26,7 +26,7 @@ v2: incorporated changes suggested by Jonas Gorski
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -2724,6 +2724,20 @@ config MIPS_O32_FP64_SUPPORT
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@@ -2725,6 +2725,20 @@ config MIPS_O32_FP64_SUPPORT
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If unsure, say N.
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|
|
|
@ -1,6 +1,6 @@
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--- a/arch/mips/Kconfig
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+++ b/arch/mips/Kconfig
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@@ -2220,6 +2220,12 @@ config MIPS_VPE_LOADER
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@@ -2221,6 +2221,12 @@ config MIPS_VPE_LOADER
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Includes a loader for loading an elf relocatable object
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onto another VPE and running it.
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|
|
|
@ -14,7 +14,7 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
|
|||
|
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--- a/arch/mips/Kconfig
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+++ 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
|
||||
|
|
|
@ -14,7 +14,7 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
|
|||
|
||||
--- 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
|
||||
|
|
Loading…
Reference in a new issue