arm64: Treat ESR_ELx as a 64-bit register

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>

1 files changed, 6 insertions, 6 deletions

diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 54f32a0675df..6e5826470bea 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -24,7 +24,7 @@ struct undef_hook {
 
 void register_undef_hook(struct undef_hook *hook);
 void unregister_undef_hook(struct undef_hook *hook);
-void force_signal_inject(int signal, int code, unsigned long address, unsigned int err);
+void force_signal_inject(int signal, int code, unsigned long address, unsigned long err);
 void arm64_notify_segfault(unsigned long addr);
 void arm64_force_sig_fault(int signo, int code, unsigned long far, const char *str);
 void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, const char *str);
@@ -57,7 +57,7 @@ static inline int in_entry_text(unsigned long ptr)
  * errors share the same encoding as an all-zeros encoding from a CPU that
  * doesn't support RAS.
  */
-static inline bool arm64_is_ras_serror(u32 esr)
+static inline bool arm64_is_ras_serror(unsigned long esr)
 {
 	WARN_ON(preemptible());
 
@@ -77,9 +77,9 @@ static inline bool arm64_is_ras_serror(u32 esr)
  * We treat them as Uncontainable.
  * Non-RAS SError's are reported as Uncontained/Uncategorized.
  */
-static inline u32 arm64_ras_serror_get_severity(u32 esr)
+static inline unsigned long arm64_ras_serror_get_severity(unsigned long esr)
 {
-	u32 aet = esr & ESR_ELx_AET;
+	unsigned long aet = esr & ESR_ELx_AET;
 
 	if (!arm64_is_ras_serror(esr)) {
 		/* Not a RAS error, we can't interpret the ESR. */
@@ -98,6 +98,6 @@ static inline u32 arm64_ras_serror_get_severity(u32 esr)
 	return aet;
 }
 
-bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr);
-void __noreturn arm64_serror_panic(struct pt_regs *regs, u32 esr);
+bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned long esr);
+void __noreturn arm64_serror_panic(struct pt_regs *regs, unsigned long esr);
 #endif