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From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com, james.morse@arm.com,
	mark.rutland@arm.com, maz@kernel.org, will@kernel.org,
	joey.gouly@arm.com
Subject: [PATCH v2 16/19] arm64: entry: split SDEI entry
Date: Wed, 19 May 2021 13:38:59 +0100	[thread overview]
Message-ID: <20210519123902.2452-17-mark.rutland@arm.com> (raw)
In-Reply-To: <20210519123902.2452-1-mark.rutland@arm.com>

We'd like to keep all the entry sequencing in entry-common.c, as this
will allow us to ensure this is all consistent, and free from any
unsound instrumentation.

Currently __sdei_handler() performs the NMI entry/exit sequences in
sdei.c. Let's split the low-level entry sequence from the event
handling, moving the former to entry-common.c and keeping the latter in
sdei.c. The event handling function is renamed to do_sdei_event(),
matching the do_${FOO}() pattern used for other exception handlers.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/include/asm/sdei.h    |  3 +++
 arch/arm64/kernel/entry-common.c | 37 +++++++++++++++++++++++++++++++
 arch/arm64/kernel/sdei.c         | 48 +++-------------------------------------
 3 files changed, 43 insertions(+), 45 deletions(-)

diff --git a/arch/arm64/include/asm/sdei.h b/arch/arm64/include/asm/sdei.h
index 63e0b92a5fbb..03d619a49d4a 100644
--- a/arch/arm64/include/asm/sdei.h
+++ b/arch/arm64/include/asm/sdei.h
@@ -37,6 +37,9 @@ struct sdei_registered_event;
 asmlinkage unsigned long __sdei_handler(struct pt_regs *regs,
 					struct sdei_registered_event *arg);
 
+unsigned long do_sdei_event(struct pt_regs *regs,
+			    struct sdei_registered_event *arg);
+
 unsigned long sdei_arch_get_entry_point(int conduit);
 #define sdei_arch_get_entry_point(x)	sdei_arch_get_entry_point(x)
 
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 801c7d479d47..301eace7613f 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -20,6 +20,7 @@
 #include <asm/kprobes.h>
 #include <asm/mmu.h>
 #include <asm/processor.h>
+#include <asm/sdei.h>
 #include <asm/stacktrace.h>
 #include <asm/sysreg.h>
 #include <asm/system_misc.h>
@@ -711,3 +712,39 @@ UNHANDLED(el0, 32, irq)
 UNHANDLED(el0, 32, fiq)
 UNHANDLED(el0, 32, error)
 #endif /* CONFIG_COMPAT */
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+asmlinkage noinstr unsigned long
+__sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg)
+{
+	unsigned long ret;
+
+	/*
+	 * We didn't take an exception to get here, so the HW hasn't
+	 * set/cleared bits in PSTATE that we may rely on.
+	 *
+	 * The original SDEI spec (ARM DEN 0054A) can be read ambiguously as to
+	 * whether PSTATE bits are inherited unchanged or generated from
+	 * scratch, and the TF-A implementation always clears PAN and always
+	 * clears UAO. There are no other known implementations.
+	 *
+	 * Subsequent revisions (ARM DEN 0054B) follow the usual rules for how
+	 * PSTATE is modified upon architectural exceptions, and so PAN is
+	 * either inherited or set per SCTLR_ELx.SPAN, and UAO is always
+	 * cleared.
+	 *
+	 * We must explicitly reset PAN to the expected state, including
+	 * clearing it when the host isn't using it, in case a VM had it set.
+	 */
+	if (system_uses_hw_pan())
+		set_pstate_pan(1);
+	else if (cpu_has_pan())
+		set_pstate_pan(0);
+
+	arm64_enter_nmi(regs);
+	ret = do_sdei_event(regs, arg);
+	arm64_exit_nmi(regs);
+
+	return ret;
+}
+#endif /* CONFIG_ARM_SDE_INTERFACE */
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index 2c7ca449dd51..e72953992743 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -231,13 +231,13 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 }
 
 /*
- * __sdei_handler() returns one of:
+ * do_sdei_event() returns one of:
  *  SDEI_EV_HANDLED -  success, return to the interrupted context.
  *  SDEI_EV_FAILED  -  failure, return this error code to firmare.
  *  virtual-address -  success, return to this address.
  */
-static __kprobes unsigned long _sdei_handler(struct pt_regs *regs,
-					     struct sdei_registered_event *arg)
+unsigned long __kprobes do_sdei_event(struct pt_regs *regs,
+				      struct sdei_registered_event *arg)
 {
 	u32 mode;
 	int i, err = 0;
@@ -292,45 +292,3 @@ static __kprobes unsigned long _sdei_handler(struct pt_regs *regs,
 
 	return vbar + 0x480;
 }
-
-static void __kprobes notrace __sdei_pstate_entry(void)
-{
-	/*
-	 * The original SDEI spec (ARM DEN 0054A) can be read ambiguously as to
-	 * whether PSTATE bits are inherited unchanged or generated from
-	 * scratch, and the TF-A implementation always clears PAN and always
-	 * clears UAO. There are no other known implementations.
-	 *
-	 * Subsequent revisions (ARM DEN 0054B) follow the usual rules for how
-	 * PSTATE is modified upon architectural exceptions, and so PAN is
-	 * either inherited or set per SCTLR_ELx.SPAN, and UAO is always
-	 * cleared.
-	 *
-	 * We must explicitly reset PAN to the expected state, including
-	 * clearing it when the host isn't using it, in case a VM had it set.
-	 */
-	if (system_uses_hw_pan())
-		set_pstate_pan(1);
-	else if (cpu_has_pan())
-		set_pstate_pan(0);
-}
-
-asmlinkage noinstr unsigned long
-__sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg)
-{
-	unsigned long ret;
-
-	/*
-	 * We didn't take an exception to get here, so the HW hasn't
-	 * set/cleared bits in PSTATE that we may rely on. Initialize PAN.
-	 */
-	__sdei_pstate_entry();
-
-	arm64_enter_nmi(regs);
-
-	ret = _sdei_handler(regs, arg);
-
-	arm64_exit_nmi(regs);
-
-	return ret;
-}
-- 
2.11.0


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  parent reply	other threads:[~2021-05-19 13:11 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-19 12:38 [PATCH v2 00/19] arm64: entry: migrate more code to C Mark Rutland
2021-05-19 12:38 ` [PATCH v2 01/19] arm64: remove redundant local_daif_mask() in bad_mode() Mark Rutland
2021-05-21 10:39   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 02/19] arm64: entry: unmask IRQ+FIQ after EL0 handling Mark Rutland
2021-05-25 16:45   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 03/19] arm64: entry: convert SError handlers to C Mark Rutland
2021-05-25 13:38   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 04/19] arm64: entry: move arm64_preempt_schedule_irq to entry-common.c Mark Rutland
2021-05-21 11:00   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 05/19] arm64: entry: move preempt logic to C Mark Rutland
2021-05-25 12:50   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 06/19] arm64: entry: add a call_on_irq_stack helper Mark Rutland
2021-05-19 14:46   ` Mark Rutland
2021-05-19 12:38 ` [PATCH v2 07/19] arm64: entry: convert IRQ+FIQ handlers to C Mark Rutland
2021-05-21 13:19   ` Joey Gouly
2021-05-21 15:23     ` Mark Rutland
2021-05-19 12:38 ` [PATCH v2 08/19] arm64: entry: organise entry handlers consistently Mark Rutland
2021-05-21 16:04   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 09/19] arm64: entry: organise entry vectors consistently Mark Rutland
2021-05-21 16:07   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 10/19] arm64: entry: consolidate EL1 exception returns Mark Rutland
2021-05-21 16:22   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 11/19] arm64: entry: move bad_mode() to entry-common.c Mark Rutland
2021-05-21 16:46   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 12/19] arm64: entry: improve bad_mode() Mark Rutland
2021-05-21 17:02   ` Joey Gouly
2021-05-21 17:10     ` Mark Rutland
2021-05-19 12:38 ` [PATCH v2 13/19] arm64: entry: template the entry asm functions Mark Rutland
2021-05-21 17:16   ` Joey Gouly
2021-05-19 12:38 ` [PATCH v2 14/19] arm64: entry: handle all vectors with C Mark Rutland
2021-05-21 15:59   ` Joey Gouly
2021-05-21 16:41     ` Mark Rutland
2021-05-19 12:38 ` [PATCH v2 15/19] arm64: entry: split bad stack entry Mark Rutland
2021-05-25 11:25   ` Joey Gouly
2021-05-19 12:38 ` Mark Rutland [this message]
2021-05-25 11:49   ` [PATCH v2 16/19] arm64: entry: split SDEI entry Joey Gouly
2021-05-19 12:39 ` [PATCH v2 17/19] arm64: entry: make NMI entry/exit functions static Mark Rutland
2021-05-21 17:21   ` Joey Gouly
2021-05-19 12:39 ` [PATCH v2 18/19] arm64: entry: don't instrument entry code with KCOV Mark Rutland
2021-05-19 12:39 ` [PATCH v2 19/19] arm64: idle: don't instrument idle " Mark Rutland

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