From 40612000599e52e792d23c998377a0fa429c4036 Mon Sep 17 00:00:00 2001 From: Julian Brown Date: Tue, 7 Feb 2017 18:29:59 +0000 Subject: [PATCH] arm: Correctly handle watchpoints for BE32 CPUs In BE32 mode, sub-word size watchpoints can fail to trigger because the address of the access is adjusted in the opcode helpers before being compared with the watchpoint registers. This patch reverses the address adjustment before performing the comparison with the help of a new CPUClass hook. This version of the patch augments and tidies up comments a little. Signed-off-by: Julian Brown Message-id: caaf64ffc72f6ae183015337b7afdbd4b8989cb6.1484929304.git.julian@codesourcery.com Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- exec.c | 1 + include/qom/cpu.h | 3 +++ qom/cpu.c | 6 ++++++ target/arm/cpu.c | 3 +++ target/arm/internals.h | 5 +++++ target/arm/op_helper.c | 22 ++++++++++++++++++++++ 6 files changed, 40 insertions(+) diff --git a/exec.c b/exec.c index 8b9ed73b15..6fa337b8d8 100644 --- a/exec.c +++ b/exec.c @@ -2115,6 +2115,7 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) return; } vaddr = (cpu->mem_io_vaddr & TARGET_PAGE_MASK) + offset; + vaddr = cc->adjust_watchpoint_address(cpu, vaddr, len); QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { if (cpu_watchpoint_address_matches(wp, vaddr, len) && (wp->flags & flags)) { diff --git a/include/qom/cpu.h b/include/qom/cpu.h index ca4d0fb1b4..45bcf21a21 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -132,6 +132,8 @@ struct TranslationBlock; * @cpu_exec_exit: Callback for cpu_exec cleanup. * @cpu_exec_interrupt: Callback for processing interrupts in cpu_exec. * @disas_set_info: Setup architecture specific components of disassembly info + * @adjust_watchpoint_address: Perform a target-specific adjustment to an + * address before attempting to match it against watchpoints. * * Represents a CPU family or model. */ @@ -195,6 +197,7 @@ typedef struct CPUClass { bool (*cpu_exec_interrupt)(CPUState *cpu, int interrupt_request); void (*disas_set_info)(CPUState *cpu, disassemble_info *info); + vaddr (*adjust_watchpoint_address)(CPUState *cpu, vaddr addr, int len); } CPUClass; #ifdef HOST_WORDS_BIGENDIAN diff --git a/qom/cpu.c b/qom/cpu.c index d57faf3ddc..0e19b1aa21 100644 --- a/qom/cpu.c +++ b/qom/cpu.c @@ -391,6 +391,11 @@ static int64_t cpu_common_get_arch_id(CPUState *cpu) return cpu->cpu_index; } +static vaddr cpu_adjust_watchpoint_address(CPUState *cpu, vaddr addr, int len) +{ + return addr; +} + static void cpu_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); @@ -415,6 +420,7 @@ static void cpu_class_init(ObjectClass *klass, void *data) k->cpu_exec_enter = cpu_common_noop; k->cpu_exec_exit = cpu_common_noop; k->cpu_exec_interrupt = cpu_common_exec_interrupt; + k->adjust_watchpoint_address = cpu_adjust_watchpoint_address; set_bit(DEVICE_CATEGORY_CPU, dc->categories); dc->realize = cpu_common_realizefn; dc->unrealize = cpu_common_unrealizefn; diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 81448caf18..4ee250cec6 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -1675,6 +1675,9 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data) cc->gdb_stop_before_watchpoint = true; cc->debug_excp_handler = arm_debug_excp_handler; cc->debug_check_watchpoint = arm_debug_check_watchpoint; +#if !defined(CONFIG_USER_ONLY) + cc->adjust_watchpoint_address = arm_adjust_watchpoint_address; +#endif cc->disas_set_info = arm_disas_set_info; } diff --git a/target/arm/internals.h b/target/arm/internals.h index 2e65bc12fa..f742a419ff 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -444,6 +444,11 @@ void hw_breakpoint_update_all(ARMCPU *cpu); /* Callback function for checking if a watchpoint should trigger. */ bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp); +/* Adjust addresses (in BE32 mode) before testing against watchpoint + * addresses. + */ +vaddr arm_adjust_watchpoint_address(CPUState *cs, vaddr addr, int len); + /* Callback function for when a watchpoint or breakpoint triggers. */ void arm_debug_excp_handler(CPUState *cs); diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index ba796d898e..fb366fdc35 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -1225,6 +1225,28 @@ bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp) return check_watchpoints(cpu); } +vaddr arm_adjust_watchpoint_address(CPUState *cs, vaddr addr, int len) +{ + ARMCPU *cpu = ARM_CPU(cs); + CPUARMState *env = &cpu->env; + + /* In BE32 system mode, target memory is stored byteswapped (on a + * little-endian host system), and by the time we reach here (via an + * opcode helper) the addresses of subword accesses have been adjusted + * to account for that, which means that watchpoints will not match. + * Undo the adjustment here. + */ + if (arm_sctlr_b(env)) { + if (len == 1) { + addr ^= 3; + } else if (len == 2) { + addr ^= 2; + } + } + + return addr; +} + void arm_debug_excp_handler(CPUState *cs) { /* Called by core code when a watchpoint or breakpoint fires;