[PATCH 04/13] arm64: sdei: move uaccess logic to arch/arm64/
flat view
STALE2206d
From: Mark Rutland <mark.rutland@arm.com>
Date: 2020-09-25 16:09:59
Subsystem:
arm64 port (aarch64 architecture), software delegated exception interface (sdei), the rest · Maintainers:
Catalin Marinas, Will Deacon, James Morse, Linus Torvalds
The SDEI support code is split across arch/arm64/ and drivers/firmware/, largley this is split so that the arch-specific portions are under arch/arm64, and the management logic is under drivers/firmware/. However, exception entry fixups are currently under drivers/firmware. Let's move the exception entry fixups under arch/arm64/. This de-clutters the management logic, and puts all the arch-specific portions in one place. Doing this also allows the fixups to be applied earlier, so things like PAN and UAO will be in a known good state before we run other logic. This will also make subsequent refactoring easier. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/kernel/sdei.c | 18 ++++++++++++------ drivers/firmware/arm_sdei.c | 14 -------------- 2 files changed, 12 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index 7689f2031c0c4..4a5f24602aa0c 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c@@ -178,12 +178,6 @@ static __kprobes unsigned long _sdei_handler(struct pt_regs *regs, sdei_api_event_context(i, ®s->regs[i]); } - /* - * We didn't take an exception to get here, set PAN. UAO will be cleared - * by sdei_event_handler()s force_uaccess_begin() call. - */ - __uaccess_enable_hw_pan(); - err = sdei_event_handler(regs, arg); if (err) return SDEI_EV_FAILED;
@@ -227,6 +221,16 @@ asmlinkage __kprobes notrace unsigned long __sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg) { unsigned long ret; + mm_segment_t orig_addr_limit; + + /* + * We didn't take an exception to get here, so the HW hasn't set PAN or + * cleared UAO, and the exception entry code hasn't reset addr_limit. + * Set PAN, then use force_uaccess_begin() to clear UAO and reset + * addr_limit. + */ + __uaccess_enable_hw_pan(); + orig_addr_limit = force_uaccess_begin(); nmi_enter();
@@ -234,5 +238,7 @@ __sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg) nmi_exit(); + force_uaccess_end(orig_addr_limit); + return ret; }
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index b4b9ce97f415e..25a87c729f090 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c@@ -31,7 +31,6 @@ #include <linux/slab.h> #include <linux/smp.h> #include <linux/spinlock.h> -#include <linux/uaccess.h> /* * The call to use to reach the firmware.
@@ -1125,26 +1124,13 @@ int sdei_event_handler(struct pt_regs *regs, struct sdei_registered_event *arg) { int err; - mm_segment_t orig_addr_limit; u32 event_num = arg->event_num; - /* - * Save restore 'fs'. - * The architecture's entry code save/restores 'fs' when taking an - * exception from the kernel. This ensures addr_limit isn't inherited - * if you interrupted something that allowed the uaccess routines to - * access kernel memory. - * Do the same here because this doesn't come via the same entry code. - */ - orig_addr_limit = force_uaccess_begin(); - err = arg->callback(event_num, regs, arg->callback_arg); if (err) pr_err_ratelimited("event %u on CPU %u failed with error: %d\n", event_num, smp_processor_id(), err); - force_uaccess_end(orig_addr_limit); - return err; } NOKPROBE_SYMBOL(sdei_event_handler);
--
2.11.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel