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, 14 insertions, 14 deletions

diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index 339477dca551..0e6535aa78c2 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -19,9 +19,9 @@
 #define __exception_irq_entry	__kprobes
 #endif
 
-static inline u32 disr_to_esr(u64 disr)
+static inline unsigned long disr_to_esr(u64 disr)
 {
-	unsigned int esr = ESR_ELx_EC_SERROR << ESR_ELx_EC_SHIFT;
+	unsigned long esr = ESR_ELx_EC_SERROR << ESR_ELx_EC_SHIFT;
 
 	if ((disr & DISR_EL1_IDS) == 0)
 		esr |= (disr & DISR_EL1_ESR_MASK);
@@ -57,23 +57,23 @@ asmlinkage void call_on_irq_stack(struct pt_regs *regs,
 				  void (*func)(struct pt_regs *));
 asmlinkage void asm_exit_to_user_mode(struct pt_regs *regs);
 
-void do_mem_abort(unsigned long far, unsigned int esr, struct pt_regs *regs);
+void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs);
 void do_undefinstr(struct pt_regs *regs);
 void do_bti(struct pt_regs *regs);
-void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr,
+void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr,
 			struct pt_regs *regs);
-void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs);
-void do_sve_acc(unsigned int esr, struct pt_regs *regs);
-void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs);
-void do_sysinstr(unsigned int esr, struct pt_regs *regs);
-void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
-void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr);
-void do_cp15instr(unsigned int esr, struct pt_regs *regs);
+void do_fpsimd_acc(unsigned long esr, struct pt_regs *regs);
+void do_sve_acc(unsigned long esr, struct pt_regs *regs);
+void do_fpsimd_exc(unsigned long esr, struct pt_regs *regs);
+void do_sysinstr(unsigned long esr, struct pt_regs *regs);
+void do_sp_pc_abort(unsigned long addr, unsigned long esr, struct pt_regs *regs);
+void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr);
+void do_cp15instr(unsigned long esr, struct pt_regs *regs);
 void do_el0_svc(struct pt_regs *regs);
 void do_el0_svc_compat(struct pt_regs *regs);
-void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr);
-void do_serror(struct pt_regs *regs, unsigned int esr);
+void do_ptrauth_fault(struct pt_regs *regs, unsigned long esr);
+void do_serror(struct pt_regs *regs, unsigned long esr);
 void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags);
 
-void panic_bad_stack(struct pt_regs *regs, unsigned int esr, unsigned long far);
+void panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far);
 #endif	/* __ASM_EXCEPTION_H */