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* arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-stepSumit Garg2023-04-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently only the first attempt to single-step has any effect. After that all further stepping remains "stuck" at the same program counter value. Refer to the ARM Architecture Reference Manual (ARM DDI 0487E.a) D2.12, PSTATE.SS=1 should be set at each step before transferring the PE to the 'Active-not-pending' state. The problem here is PSTATE.SS=1 is not set since the second single-step. After the first single-step, the PE transferes to the 'Inactive' state, with PSTATE.SS=0 and MDSCR.SS=1, thus PSTATE.SS won't be set to 1 due to kernel_active_single_step()=true. Then the PE transferes to the 'Active-pending' state when ERET and returns to the debugger by step exception. Before this patch: ================== Entering kdb (current=0xffff3376039f0000, pid 1) on processor 0 due to Keyboard Entry [0]kdb> [0]kdb> [0]kdb> bp write_sysrq_trigger Instruction(i) BP #0 at 0xffffa45c13d09290 (write_sysrq_trigger) is enabled addr at ffffa45c13d09290, hardtype=0 installed=0 [0]kdb> go $ echo h > /proc/sysrq-trigger Entering kdb (current=0xffff4f7e453f8000, pid 175) on processor 1 due to Breakpoint @ 0xffffad651a309290 [1]kdb> ss Entering kdb (current=0xffff4f7e453f8000, pid 175) on processor 1 due to SS trap @ 0xffffad651a309294 [1]kdb> ss Entering kdb (current=0xffff4f7e453f8000, pid 175) on processor 1 due to SS trap @ 0xffffad651a309294 [1]kdb> After this patch: ================= Entering kdb (current=0xffff6851c39f0000, pid 1) on processor 0 due to Keyboard Entry [0]kdb> bp write_sysrq_trigger Instruction(i) BP #0 at 0xffffc02d2dd09290 (write_sysrq_trigger) is enabled addr at ffffc02d2dd09290, hardtype=0 installed=0 [0]kdb> go $ echo h > /proc/sysrq-trigger Entering kdb (current=0xffff6851c53c1840, pid 174) on processor 1 due to Breakpoint @ 0xffffc02d2dd09290 [1]kdb> ss Entering kdb (current=0xffff6851c53c1840, pid 174) on processor 1 due to SS trap @ 0xffffc02d2dd09294 [1]kdb> ss Entering kdb (current=0xffff6851c53c1840, pid 174) on processor 1 due to SS trap @ 0xffffc02d2dd09298 [1]kdb> ss Entering kdb (current=0xffff6851c53c1840, pid 174) on processor 1 due to SS trap @ 0xffffc02d2dd0929c [1]kdb> Fixes: 44679a4f142b ("arm64: KGDB: Add step debugging support") Co-developed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Tested-by: Douglas Anderson <dianders@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20230202073148.657746-3-sumit.garg@linaro.org Signed-off-by: Will Deacon <will@kernel.org>
* arm64: Treat ESR_ELx as a 64-bit registerAlexandru Elisei2022-04-291-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the initial release of the ARM Architecture Reference Manual for ARMv8-A, the ESR_ELx registers were defined as 32-bit registers. This changed in 2018 with version D.a (ARM DDI 0487D.a) of the architecture, when they became 64-bit registers, with bits [63:32] defined as RES0. In version G.a, a new field was added to ESR_ELx, ISS2, which covers bits [36:32]. This field is used when the Armv8.7 extension FEAT_LS64 is implemented. As a result of the evolution of the register width, Linux stores it as both a 64-bit value and a 32-bit value, which hasn't affected correctness so far as Linux only uses the lower 32 bits of the register. Make the register type consistent and always treat it as 64-bit wide. The register is redefined as an "unsigned long", which is an unsigned double-word (64-bit quantity) for the LP64 machine (aapcs64 [1], Table 1, page 14). The type was chosen because "unsigned int" is the most frequent type for ESR_ELx and because FAR_ELx, which is used together with ESR_ELx in exception handling, is also declared as "unsigned long". The 64-bit type also makes adding support for architectural features that use fields above bit 31 easier in the future. The KVM hypervisor will receive a similar update in a subsequent patch. [1] https://github.com/ARM-software/abi-aa/releases/download/2021Q3/aapcs64.pdf Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425114444.368693-4-alexandru.elisei@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: insn: decouple patching from insn codeMark Rutland2021-06-111-0/+1
| | | | | | | | | | | | | | | | | | | | | Currently, <asm/insn.h> includes <asm/patching.h>. We intend that <asm/insn.h> will be usable from userspace, so it doesn't make sense to include headers for kernel-only features such as the patching routines, and we'd intended to restrict <asm/insn.h> to instruction encoding details. Let's decouple the patching code from <asm/insn.h>, and explicitly include <asm/patching.h> where it is needed. Since <asm/patching.h> isn't included from assembly, we can drop the __ASSEMBLY__ guards. At the same time, sort the kprobes includes so that it's easier to see what is and isn't incldued. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210609102301.17332-2-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
* arm64: kgdb: Fix single-step exception handling oopsWei Li2020-07-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After entering kdb due to breakpoint, when we execute 'ss' or 'go' (will delay installing breakpoints, do single-step first), it won't work correctly, and it will enter kdb due to oops. It's because the reason gotten in kdb_stub() is not as expected, and it seems that the ex_vector for single-step should be 0, like what arch powerpc/sh/parisc has implemented. Before the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 due to Breakpoint @ 0xffff8000101486cc [3]kdb> ss Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 Oops: (null) due to oops @ 0xffff800010082ab8 CPU: 3 PID: 266 Comm: sh Not tainted 5.7.0-rc4-13839-gf0e5ad491718 #6 Hardware name: linux,dummy-virt (DT) pstate: 00000085 (nzcv daIf -PAN -UAO) pc : el1_irq+0x78/0x180 lr : __handle_sysrq+0x80/0x190 sp : ffff800015003bf0 x29: ffff800015003d20 x28: ffff0000fa878040 x27: 0000000000000000 x26: ffff80001126b1f0 x25: ffff800011b6a0d8 x24: 0000000000000000 x23: 0000000080200005 x22: ffff8000101486cc x21: ffff800015003d30 x20: 0000ffffffffffff x19: ffff8000119f2000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : ffff800015003e50 x7 : 0000000000000002 x6 : 00000000380b9990 x5 : ffff8000106e99e8 x4 : ffff0000fadd83c0 x3 : 0000ffffffffffff x2 : ffff800011b6a0d8 x1 : ffff800011b6a000 x0 : ffff80001130c9d8 Call trace: el1_irq+0x78/0x180 printk+0x0/0x84 write_sysrq_trigger+0xb0/0x118 proc_reg_write+0xb4/0xe0 __vfs_write+0x18/0x40 vfs_write+0xb0/0x1b8 ksys_write+0x64/0xf0 __arm64_sys_write+0x14/0x20 el0_svc_common.constprop.2+0xb0/0x168 do_el0_svc+0x20/0x98 el0_sync_handler+0xec/0x1a8 el0_sync+0x140/0x180 [3]kdb> After the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> g Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> ss Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to SS trap @ 0xffff800010082ab8 [0]kdb> Fixes: 44679a4f142b ("arm64: KGDB: Add step debugging support") Signed-off-by: Wei Li <liwei391@huawei.com> Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200509214159.19680-2-liwei391@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234Thomas Gleixner2019-06-191-12/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): 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 this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* arm64: debug: Remove redundant user_mode(regs) checks from debug handlersWill Deacon2019-04-091-7/+1
| | | | | | | | | Now that the debug hook dispatching code takes the triggering exception level into account, there's no need for the hooks themselves to poke around with user_mode(regs). Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: debug: Separate debug hooks based on target exception levelWill Deacon2019-04-091-12/+10
| | | | | | | | | | | | | | Mixing kernel and user debug hooks together is highly error-prone as it relies on all of the hooks to figure out whether the exception came from kernel or user, and then to act accordingly. Make our debug hook code a little more robust by maintaining separate hook lists for user and kernel, with separate registration functions to force callers to be explicit about the exception levels that they care about. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: debug: Ensure debug handlers check triggering exception levelWill Deacon2019-03-011-4/+10
| | | | | | | | | | | | | | | | | | Debug exception handlers may be called for exceptions generated both by user and kernel code. In many cases, this is checked explicitly, but in other cases things either happen to work by happy accident or they go slightly wrong. For example, executing 'brk #4' from userspace will enter the kprobes code and be ignored, but the instruction will be retried forever in userspace instead of delivering a SIGTRAP. Fix this issue in the most stable-friendly fashion by simply adding explicit checks of the triggering exception level to all of our debug exception handlers. Cc: <stable@vger.kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kgdb/treewide: constify struct kgdb_arch arch_kgdb_opsChristophe Leroy2018-12-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | checkpatch.pl reports the following: WARNING: struct kgdb_arch should normally be const #28: FILE: arch/mips/kernel/kgdb.c:397: +struct kgdb_arch arch_kgdb_ops = { This report makes sense, as all other ops struct, this one should also be const. This patch does the change. Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Ley Foon Tan <lftan@altera.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: x86@kernel.org Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Paul Burton <paul.burton@mips.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
* kgdb: Fix kgdb_roundup_cpus() for arches who used smp_call_function()Douglas Anderson2018-12-301-12/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I had lockdep turned on and dropped into kgdb I got a nice splat on my system. Specifically it hit: DEBUG_LOCKS_WARN_ON(current->hardirq_context) Specifically it looked like this: sysrq: SysRq : DEBUG ------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(current->hardirq_context) WARNING: CPU: 0 PID: 0 at .../kernel/locking/lockdep.c:2875 lockdep_hardirqs_on+0xf0/0x160 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.0 #27 pstate: 604003c9 (nZCv DAIF +PAN -UAO) pc : lockdep_hardirqs_on+0xf0/0x160 ... Call trace: lockdep_hardirqs_on+0xf0/0x160 trace_hardirqs_on+0x188/0x1ac kgdb_roundup_cpus+0x14/0x3c kgdb_cpu_enter+0x53c/0x5cc kgdb_handle_exception+0x180/0x1d4 kgdb_compiled_brk_fn+0x30/0x3c brk_handler+0x134/0x178 do_debug_exception+0xfc/0x178 el1_dbg+0x18/0x78 kgdb_breakpoint+0x34/0x58 sysrq_handle_dbg+0x54/0x5c __handle_sysrq+0x114/0x21c handle_sysrq+0x30/0x3c qcom_geni_serial_isr+0x2dc/0x30c ... ... irq event stamp: ...45 hardirqs last enabled at (...44): [...] __do_softirq+0xd8/0x4e4 hardirqs last disabled at (...45): [...] el1_irq+0x74/0x130 softirqs last enabled at (...42): [...] _local_bh_enable+0x2c/0x34 softirqs last disabled at (...43): [...] irq_exit+0xa8/0x100 ---[ end trace adf21f830c46e638 ]--- Looking closely at it, it seems like a really bad idea to be calling local_irq_enable() in kgdb_roundup_cpus(). If nothing else that seems like it could violate spinlock semantics and cause a deadlock. Instead, let's use a private csd alongside smp_call_function_single_async() to round up the other CPUs. Using smp_call_function_single_async() doesn't require interrupts to be enabled so we can remove the offending bit of code. In order to avoid duplicating this across all the architectures that use the default kgdb_roundup_cpus(), we'll add a "weak" implementation to debug_core.c. Looking at all the people who previously had copies of this code, there were a few variants. I've attempted to keep the variants working like they used to. Specifically: * For arch/arc we passed NULL to kgdb_nmicallback() instead of get_irq_regs(). * For arch/mips there was a bit of extra code around kgdb_nmicallback() NOTE: In this patch we will still get into trouble if we try to round up a CPU that failed to round up before. We'll try to round it up again and potentially hang when we try to grab the csd lock. That's not new behavior but we'll still try to do better in a future patch. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
* kgdb: Remove irq flags from roundupDouglas Anderson2018-12-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function kgdb_roundup_cpus() was passed a parameter that was documented as: > the flags that will be used when restoring the interrupts. There is > local_irq_save() call before kgdb_roundup_cpus(). Nobody used those flags. Anyone who wanted to temporarily turn on interrupts just did local_irq_enable() and local_irq_disable() without looking at them. So we can definitely remove the flags. Signed-off-by: Douglas Anderson <dianders@chromium.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
* arm64/debug: Fix registers on sleeping tasksDouglas Anderson2018-03-061-5/+16
| | | | | | | | | | | | This is the equivalent of commit 001bf455d206 ("ARM: 8428/1: kgdb: Fix registers on sleeping tasks") but for arm64. Nuff said. ...well, perhaps I could also add that task_pt_regs are userspace registers and that's not what kgdb is supposed to be reporting. We're supposed to be reporting kernel registers. Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+2
| | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* arm64: kgdb_step_brk_fn: ignore other's exceptionPratyush Anand2016-11-071-0/+3
| | | | | | | | | | | | | | | ARM64 step exception does not have any syndrome information. So, it is responsibility of exception handler to take care that they handle it only if exception was raised for them. Since kgdb_step_brk_fn() always returns 0, therefore we might have problem when we will have other step handler registered as well. This patch fixes kgdb_step_brk_fn() to return error in case of step handler was not meant for kgdb. Signed-off-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: kgdb: handle read-only text / modulesAKASHI Takahiro2016-09-231-12/+24
| | | | | | | | | | | | | | Handle read-only cases when CONFIG_DEBUG_RODATA (4.0) or CONFIG_DEBUG_SET_MODULE_RONX (3.18) are enabled by using aarch64_insn_write() instead of probe_kernel_write() as introduced by commit 2f896d586610 ("arm64: use fixmap for text patching") in 4.0. Fixes: 11d91a770f1f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support") Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: Blacklist non-kprobe-able symbolPratyush Anand2016-07-191-0/+4
| | | | | | | | | Add all function symbols which are called from do_debug_exception under NOKPROBE_SYMBOL, as they can not kprobed. Signed-off-by: Pratyush Anand <panand@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: kgdb: Match pstate size with gdbserver protocolDaniel Thompson2016-06-161-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current versions of gdb do not interoperate cleanly with kgdb on arm64 systems because gdb and kgdb do not use the same register description. This patch modifies kgdb to work with recent releases of gdb (>= 7.8.1). Compatibility with gdb (after the patch is applied) is as follows: gdb-7.6 and earlier Ok gdb-7.7 series Works if user provides custom target description gdb-7.8(.0) Works if user provides custom target description gdb-7.8.1 and later Ok When commit 44679a4f142b ("arm64: KGDB: Add step debugging support") was introduced it was paired with a gdb patch that made an incompatible change to the gdbserver protocol. This patch was eventually merged into the gdb sources: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=a4d9ba85ec5597a6a556afe26b712e878374b9dd The change to the protocol was mostly made to simplify big-endian support inside the kernel gdb stub. Unfortunately the gdb project released gdb-7.7.x and gdb-7.8.0 before the protocol incompatibility was identified and reversed: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=bdc144174bcb11e808b4e73089b850cf9620a7ee This leaves us in a position where kgdb still uses the no-longer-used protocol; gdb-7.8.1, which restored the original behaviour, was released on 2014-10-29. I don't believe it is possible to detect/correct the protocol incompatiblity which means the kernel must take a view about which version of the gdb remote protocol is "correct". This patch takes the view that the original/current version of the protocol is correct and that version found in gdb-7.7.x and gdb-7.8.0 is anomalous. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: Fix misspellings in comments.Adam Buchbinder2016-03-041-2/+2
| | | | | Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64/debug: Simplify BRK insn opcode declarationsDave P Martin2015-07-271-6/+6
| | | | | | | | | | | | | | | | | | | | The way the KGDB_DYN_BRK_INS_BYTEx macros are declared is more complex than it needs to be. Also, the macros are only used in one place, which is arch-specific anyway. This patch refactors the macros to simplify them, and exposes an argument so that we can have a single macro instead of 4. As a side effect, this patch also fixes some anomalous spellings of "KGDB". These changes alter the compile types of some integer constants that are harmless but trigger truncation warnings in gcc when assigning to 32-bit variables. This patch adds an explicit cast for the affected cases. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64/debug: More consistent naming for the BRK ESR template macroDave P Martin2015-07-271-2/+2
| | | | | | | | | | | | | | The naming of DBG_ESR_VAL_BRK is inconsistent with the way other similar macros are named. This patch makes the naming more consistent, and appends "64" as a reminder that this ESR pattern only matches from AArch64 state. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: Fix typos in KGDB macrosCatalin Marinas2014-09-251-2/+2
| | | | | | | Some of the KGDB macros used for generating the BRK instructions had the wrong spelling for DBG and KGDB abbreviations. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: KGDB: Add step debugging supportVijaya Kumar K2014-02-261-8/+56
| | | | | | | | | | | | | | | | Add KGDB software step debugging support for EL1 debug in AArch64 mode. KGDB registers step debug handler with debug monitor. On receiving 'step' command from GDB tool, target enables software step debugging and step address is updated in ELR. Software Step debugging is disabled when 'continue' command is received Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: KGDB: Add Basic KGDB supportVijaya Kumar K2014-02-261-0/+288
Add KGDB debug support for kernel debugging. With this patch, basic KGDB debugging is possible.GDB register layout is updated and GDB tool can establish connection with target and can set/clear breakpoints. Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>