[PATCH 2/2] arm64: Unify kernel fault reporting
From: mark.rutland@arm.com (Mark Rutland)
Date: 2018-05-21 13:14:51
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
In do_page_fault(), we handle some kernel faults early, and simply die() with a message. For faults handled later, we dump the faulting address, decode the ESR, walk the page tables, and perform a number of steps to ensure that this data is reported. Let's unify the handling of fatal kernel faults with a new die_kernel_fault() helper, handling all of these details. This is largely the same as the existing logic in __do_kernel_fault(), except that addresses are consistently padded to 16 hex characters, as would be expected for a 64-bit address. The messages currently logged in do_page_fault are adjusted to fit into the die_kernel_fault() message template. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> --- arch/arm64/mm/fault.c | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 59990491e72a..27cbe0b38960 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c@@ -255,6 +255,22 @@ static inline bool is_el1_permission_fault(unsigned int esr, return false; } +static void die_kernel_fault(const char *msg, unsigned long addr, + unsigned int esr, struct pt_regs *regs) +{ + bust_spinlocks(1); + + pr_alert("Unable to handle kernel %s at virtual address %016lx\n", msg, + addr); + + mem_abort_decode(esr); + + show_pte(addr); + die("Oops", regs, esr); + bust_spinlocks(0); + do_exit(SIGKILL); +} + static void __do_kernel_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) {
@@ -267,8 +283,6 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) return; - bust_spinlocks(1); - if (is_el1_permission_fault(esr, regs, addr)) { if (esr & ESR_ELx_WNR) msg = "write to read-only memory";
@@ -280,15 +294,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, msg = "paging request"; } - pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg, - addr); - - mem_abort_decode(esr); - - show_pte(addr); - die("Oops", regs, esr); - bust_spinlocks(0); - do_exit(SIGKILL); + die_kernel_fault(msg, addr, esr, regs); } static void __do_user_fault(struct siginfo *info, unsigned int esr)
@@ -399,13 +405,16 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, if (addr < TASK_SIZE && is_el1_permission_fault(esr, regs, addr)) { /* regs->orig_addr_limit may be 0 if we entered from EL0 */ if (regs->orig_addr_limit == KERNEL_DS) - die("Accessing user space memory with fs=KERNEL_DS", regs, esr); + die_kernel_fault("access to user memory with fs=KERNEL_DS", + addr, esr, regs); if (is_el1_instruction_abort(esr)) - die("Attempting to execute userspace memory", regs, esr); + die_kernel_fault("execution of user memory", + addr, esr, regs); if (!search_exception_tables(regs->pc)) - die("Accessing user space memory outside uaccess.h routines", regs, esr); + die_kernel_fault("access to user memory outside uaccess routines", + addr, esr, regs); } perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
--
2.11.0