ARM: KDB FIQ debugger
Subsystems (4)
v10 cover ARM: KDB FIQ debugger
Hello Russell,
The KDB/NMI core support has been merged into v3.7-rc1, so the only ARM bits are pending now. I believe I addressed all your previous comments, but surely there might be something else to improve, thus would be great if you could take a look at this.
The patches were rebased onto v3.7-rc1, and this is the only change in v10.
Old changelogs and rationale for these patches can be found here:
v1-v5, rationale: http://lkml.org/lkml/2012/9/10/2 v6: http://lkml.org/lkml/2012/9/10/2 v7: http://lkml.org/lkml/2012/9/13/367 v8: http://lkml.org/lkml/2012/9/19/525 v9: http://lkml.org/lkml/2012/9/24/538
Thanks!
Anton.
--
arch/arm/Kconfig | 19 ++++ arch/arm/common/vic.c | 28 +++++ arch/arm/include/asm/hardware/vic.h | 2 + arch/arm/include/asm/kgdb.h | 8 ++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/entry-armv.S | 167 +--------------------------- arch/arm/kernel/entry-header.S | 170 +++++++++++++++++++++++++++++ arch/arm/kernel/kgdb_fiq.c | 124 +++++++++++++++++++++ arch/arm/kernel/kgdb_fiq_entry.S | 87 +++++++++++++++ arch/arm/mach-versatile/Makefile | 1 + arch/arm/mach-versatile/kgdb_fiq.c | 31 ++++++ 11 files changed, 472 insertions(+), 166 deletions(-)
PATCH v10 1/4 ARM: Move some macros from entry-armv to entry-header
Just move the macros into header file as we would want to use them for KGDB FIQ entry code.
The following macros were moved:
- svc_entry
- usr_entry
- kuser_cmpxchg_check
- vector_stub
To make kuser_cmpxchg_check actually work across different files, we also have to make kuser_cmpxchg64_fixup global.
Signed-off-by Anton Vorontsov <[email protected]>
--- arch/arm/kernel/entry-armv.S | 167 +--------------------------------------- arch/arm/kernel/entry-header.S | 170 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 171 insertions(+), 166 deletions(-)
arch/arm/kernel/entry-armv.S +1 -166
@@ -136,57 +136,6 @@ common_invalid: b bad_mode ENDPROC(__und_invalid) -/* - * SVC mode handlers - */ - -#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) -#define SPFIX(code...) code -#else -#define SPFIX(code...) -#endif - - .macro svc_entry, stack_hole=0 - UNWIND(.fnstart ) - UNWIND(.save {r0 - pc} ) - sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4) -#ifdef CONFIG_THUMB2_KERNEL - SPFIX( str r0, [sp] ) @ temporarily saved - SPFIX( mov r0, sp ) - SPFIX( tst r0, #4 ) @ test original stack alignment - SPFIX( ldr r0, [sp] ) @ restored -#else - SPFIX( tst sp, #4 ) -#endif - SPFIX( subeq sp, sp, #4 ) - stmia sp, {r1 - r12} - - ldmia r0, {r3 - r5} - add r7, sp, #S_SP - 4 @ here for interlock avoidance - mov r6, #-1 @ "" "" "" "" - add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4) - SPFIX( addeq r2, r2, #4 ) - str r3, [sp, #-4]! @ save the "real" r0 copied - @ from the exception stack - - mov r3, lr - - @ - @ We are now ready to fill in the remaining blanks on the stack: - @ - @ r2 - sp_svc - @ r3 - lr_svc - @ r4 - lr_<exception>, already fixed up for correct return/restart - @ r5 - spsr_<exception> - @ r6 - orig_r0 (see pt_regs definition in ptrace.h) - @ - stmia r7, {r2 - r6} - -#ifdef CONFIG_TRACE_IRQFLAGS - bl trace_hardirqs_off -#endif - .endm - .align 5 __dabt_svc: svc_entry
@@ -348,71 +297,8 @@ ENDPROC(__pabt_svc) /* * User mode handlers - * - * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE */ -#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) -#error "sizeof(struct pt_regs) must be a multiple of 8" -#endif - - .macro usr_entry - UNWIND(.fnstart ) - UNWIND(.cantunwind ) @ don't unwind the user space - sub sp, sp, #S_FRAME_SIZE - ARM( stmib sp, {r1 - r12} ) - THUMB( stmia sp, {r0 - r12} ) - - ldmia r0, {r3 - r5} - add r0, sp, #S_PC @ here for interlock avoidance - mov r6, #-1 @ "" "" "" "" - - str r3, [sp] @ save the "real" r0 copied - @ from the exception stack - - @ - @ We are now ready to fill in the remaining blanks on the stack: - @ - @ r4 - lr_<exception>, already fixed up for correct return/restart - @ r5 - spsr_<exception> - @ r6 - orig_r0 (see pt_regs definition in ptrace.h) - @ - @ Also, separately save sp_usr and lr_usr - @ - stmia r0, {r4 - r6} - ARM( stmdb r0, {sp, lr}^ ) - THUMB( store_user_sp_lr r0, r1, S_SP - S_PC ) - - @ - @ Enable the alignment trap while in kernel mode - @ - alignment_trap r0 - - @ - @ Clear FP to mark the first stack frame - @ - zero_fp - -#ifdef CONFIG_IRQSOFF_TRACER - bl trace_hardirqs_off -#endif - .endm - - .macro kuser_cmpxchg_check -#if !defined(CONFIG_CPU_32v6K) && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG) -#ifndef CONFIG_MMU -#warning "NPTL on non MMU needs fixing" -#else - @ Make sure our user space atomic helper is restarted - @ if it was interrupted in a critical region. Here we - @ perform a quick test inline since it should be false - @ 99.9999% of the time. The rest is done out of line. - cmp r4, #TASK_SIZE - blhs kuser_cmpxchg64_fixup -#endif -#endif - .endm - .align 5 __dabt_usr: usr_entry
@@ -846,6 +732,7 @@ __kuser_cmpxchg64: @ 0xffff0f60 ldmfd sp!, {r4, r5, r6, pc} .text + .global kuser_cmpxchg64_fixup kuser_cmpxchg64_fixup: @ Called from kuser_cmpxchg_fixup. @ r4 = address of interrupted insn (must be preserved).
@@ -976,58 +863,6 @@ __kuser_helper_end: THUMB( .thumb ) -/* - * Vector stubs. - * - * This code is copied to 0xffff0200 so we can use branches in the - * vectors, rather than ldr's. Note that this code must not - * exceed 0x300 bytes. - * - * Common stub entry macro: - * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC - * - * SP points to a minimal amount of processor-private memory, the address - * of which is copied into r0 for the mode specific abort handler. - */ - .macro vector_stub, name, mode, correction=0 - .align 5 - -vector_\name: - .if \correction - sub lr, lr, #\correction - .endif - - @ - @ Save r0, lr_<exception> (parent PC) and spsr_<exception> - @ (parent CPSR) - @ - stmia sp, {r0, lr} @ save r0, lr - mrs lr, spsr - str lr, [sp, #8] @ save spsr - - @ - @ Prepare for SVC32 mode. IRQs remain disabled. - @ - mrs r0, cpsr - eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE) - msr spsr_cxsf, r0 - - @ - @ the branch table must immediately follow this code - @ - and lr, lr, #0x0f - THUMB( adr r0, 1f ) - THUMB( ldr lr, [r0, lr, lsl #2] ) - mov r0, sp - ARM( ldr lr, [pc, lr, lsl #2] ) - movs pc, lr @ branch to handler in SVC mode -ENDPROC(vector_\name) - - .align 2 - @ handler addresses follow this label -1: - .endm - .globl __stubs_start __stubs_start: /*
arch/arm/kernel/entry-header.S +170 -0
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Signature · 1 line
1.7.12.3
PATCH v10 2/4 ARM: Add KGDB/KDB FIQ debugger generic code
In reply to Anton VorontsovThe FIQ debugger may be used to debug situations when the kernel stuck in uninterruptable sections, e.g. the kernel infinitely loops or deadlocked in an interrupt or with interrupts disabled.
By default KGDB FIQ is disabled in runtime, but can be enabled with kgdb_fiq.enable=1 kernel command line option.
Signed-off-by Anton Vorontsov <[email protected]>
--- arch/arm/Kconfig | 18 ++++++ arch/arm/include/asm/kgdb.h | 8 +++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/kgdb_fiq.c | 124 +++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/kgdb_fiq_entry.S | 87 +++++++++++++++++++++++++++ 5 files changed, 238 insertions(+) create mode 100644 arch/arm/kernel/kgdb_fiq.c create mode 100644 arch/arm/kernel/kgdb_fiq_entry.S
arch/arm/Kconfig +18 -0
@@ -177,6 +177,24 @@ config GENERIC_ISA_DMA config FIQ bool +config ARCH_MIGHT_HAVE_KGDB_FIQ + bool + +config KGDB_FIQ + bool "KGDB/KDB FIQ debugger" + depends on KGDB_KDB && ARCH_MIGHT_HAVE_KGDB_FIQ && !THUMB2_KERNEL + select FIQ + help + The FIQ debugger may be used to debug situations when the + kernel stuck in uninterruptable sections, e.g. the kernel + infinitely loops or deadlocked in an interrupt or with + interrupts disabled. + + By default KGDB FIQ is disabled in runtime, but can be + enabled with kgdb_fiq.enable=1 kernel command line option. + + If unsure, say N. + config NEED_RET_TO_USER bool
arch/arm/include/asm/kgdb.h +8 -0
@@ -11,6 +11,8 @@#define __ARM_KGDB_H__#include <linux/ptrace.h> +#include <linux/linkage.h> +#include <asm/exception.h> /* * GDB assumes that we're a user process being debugged, so
@@ -47,6 +49,12 @@ static inline void arch_kgdb_breakpoint(void)extern void kgdb_handle_bus_error (void );extern int kgdb_fault_expected; +extern char kgdb_fiq_handler; +extern char kgdb_fiq_handler_end; +asmlinkage void __exception_irq_entry kgdb_fiq_do_handle(struct pt_regs *regs); +extern int __init kgdb_register_fiq (unsigned int mach_kgdb_fiq, +void (*mach_kgdb_enable_fiq)(unsigned int irq,bool on), +bool (*mach_is_kgdb_fiq)(unsigned int irq));#endif /* !__ASSEMBLY__ */ /*
arch/arm/kernel/Makefile +1 -0
@@ -56,6 +56,7 @@ endif obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o obj-$(CONFIG_ARM_THUMBEE) += thumbee.o obj-$(CONFIG_KGDB) += kgdb.o +obj-$(CONFIG_KGDB_FIQ) += kgdb_fiq_entry.o kgdb_fiq.o obj-$(CONFIG_ARM_UNWIND) += unwind.o obj-$(CONFIG_HAVE_TCM) += tcm.o obj-$(CONFIG_OF) += devtree.o
arch/arm/kernel/kgdb_fiq.c new file +124 -0
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arch/arm/kernel/kgdb_fiq_entry.S new file +87 -0
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Signature · 1 line
1.7.12.3
PATCH v10 3/4 ARM: VIC: Add a couple of low-level FIQ management helpers
In reply to Anton VorontsovJust a couple of calls to manage VIC FIQ routing. We'll use them for KGDB FIQ support on ARM Versatile machines.
Signed-off-by Anton Vorontsov <[email protected]>
--- arch/arm/common/vic.c | 28 ++++++++++++++++++++++++++++ arch/arm/include/asm/hardware/vic.h | 2 ++ 2 files changed, 30 insertions(+)
arch/arm/common/vic.c +28 -0
@@ -66,6 +66,34 @@ static struct vic_device vic_devices[CONFIG_ARM_VIC_NR];static int vic_id; +static void __iomem *vic_base (struct irq_data *d) +{ +return (void __iomem *)irq_data_get_irq_chip_data (d); +} + +void vic_fiq_select (unsigned int irq,bool on) +{ +void __iomem *base =vic_base (&irq_to_desc (irq)->irq_data); +void __iomem *sel = base +VIC_INT_SELECT ; +u32 msk =1 << irq; +u32 val; + +pr_debug ("rerouting VIC vector %d to %s\n" , irq, on ?"FIQ" :"IRQ" ); + + val =readl (sel); + val &= ~msk; +if (on) + val |= msk; +writel (val, sel); +} + +bool vic_is_fiq_rised (unsigned int irq) +{ +void __iomem *base =vic_base (&irq_to_desc (irq)->irq_data); + +return readl (base +VIC_FIQ_STATUS ) & (1 << irq); +} +/** * vic_init2 - common initialisation code * @base: Base of the VIC.
arch/arm/include/asm/hardware/vic.h +2 -0
@@ -52,6 +52,8 @@ void __vic_init(void __iomem *base, unsigned int irq_start, u32 vic_sources,void vic_init (void __iomem *base,unsigned int irq_start,u32 vic_sources,u32 resume_sources);int vic_of_init (struct device_node *node,struct device_node *parent);void vic_handle_irq (struct pt_regs *regs); +void vic_fiq_select (unsigned int irq,bool on); +bool vic_is_fiq_rised (unsigned int irq);#endif /* __ASSEMBLY__ */ #endif
Signature · 1 line
1.7.12.3
PATCH v10 4/4 ARM: versatile: Make able to use UART ports for KGDB FIQ debugger
In reply to Anton VorontsovIf enabled, kernel will able to enter KGDB upon serial line activity on UART ports.
Note that even with this patch and CONFIG_KGDB_FIQ is enabled, you still need to pass kgdb_fiq.enable=1 kernel command line option, otherwise UART will behave in a normal way.
By default UART0 is used, but this can be changed via kgdb_fiq.uart_num kernel command line option.
Signed-off-by Anton Vorontsov <[email protected]>
--- arch/arm/Kconfig | 1 + arch/arm/mach-versatile/Makefile | 1 + arch/arm/mach-versatile/kgdb_fiq.c | 31 +++++++++++++++++++++++++++++++ 3 files changed, 33 insertions(+) create mode 100644 arch/arm/mach-versatile/kgdb_fiq.c
arch/arm/Kconfig +1 -0
@@ -337,6 +337,7 @@ config ARCH_VERSATILE select PLAT_VERSATILE_CLCD select PLAT_VERSATILE_CLOCK select PLAT_VERSATILE_FPGA_IRQ + select ARCH_MIGHT_HAVE_KGDB_FIQ help This enables support for ARM Ltd Versatile board.
arch/arm/mach-versatile/Makefile +1 -0
@@ -7,3 +7,4 @@ obj-$(CONFIG_ARCH_VERSATILE_PB) += versatile_pb.o obj-$(CONFIG_MACH_VERSATILE_AB) += versatile_ab.o obj-$(CONFIG_MACH_VERSATILE_DT) += versatile_dt.o obj-$(CONFIG_PCI) += pci.o +obj-$(CONFIG_KGDB_FIQ) += kgdb_fiq.o
arch/arm/mach-versatile/kgdb_fiq.c new file +31 -0
@@ -0,0 +1,31 @@ +/* +* KGDB FIQ board support +* +* Copyright 2012 Linaro Ltd. +* Anton Vorontsov <[email protected]> +* +* This program is free software; you can redistribute it and/or modify it +* under the terms of the GNU General Public License version 2 as published +* by the Free Software Foundation. +*/ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kgdb.h> +#include <mach/hardware.h> +#include <mach/platform.h> +#include <asm/hardware/vic.h> + +static int kgdb_fiq; +module_param_named (uart_num, kgdb_fiq, int,0600 ); +MODULE_PARM_DESC (uart_num,"UART<number> port to use for KGDB FIQ" ); + +static int __init kgdb_fiq_init (void ) +{ +WARN_ON (kgdb_fiq >INT_UARTINT2 -INT_UARTINT0 ); + +return kgdb_register_fiq (INT_UARTINT0 + kgdb_fiq, + vic_fiq_select, + vic_is_fiq_rised); +} +console_initcall (kgdb_fiq_init);
Signature · 1 line
1.7.12.3
Quoted 10 lines · Anton Vorontsov
Hello Russell,
The KDB/NMI core support has been merged into v3.7-rc1, so the only ARM bits are pending now. I believe I addressed all your previous comments, but surely there might be something else to improve, thus would be great if you could take a look at this.
The patches were rebased onto v3.7-rc1, and this is the only change in v10.
Quoted 7 lines
Old changelogs and rationale for these patches can be found here:
v1-v5, rationale: http://lkml.org/lkml/2012/9/10/2 v6: http://lkml.org/lkml/2012/9/10/2 v7: http://lkml.org/lkml/2012/9/13/367 v8: http://lkml.org/lkml/2012/9/19/525 v9: http://lkml.org/lkml/2012/9/24/538
Just catching up from being on leave, but I've not seen any response to this.
Are there objections to this patch set? Or did it just get buried in everyone's inbox?
thanks
-john