arm64: add C wrappers for SET_PSTATE_*()

To make callsites easier to read, add trivial C wrappers for the
SET_PSTATE_*() helpers, and convert trivial uses over to these. The new
wrappers will be used further in subsequent patches.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: James Morse <[e-mail]>
Cc: Will Deacon <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Catalin Marinas <[e-mail]>

arch/arm64/include/asm/sysreg.h

···
 #define SET_PSTATE_SSBS(x)		__emit_inst(0xd500401f | PSTATE_SSBS | ((!!x) << PSTATE_Imm_shift))
 #define SET_PSTATE_TCO(x)		__emit_inst(0xd500401f | PSTATE_TCO | ((!!x) << PSTATE_Imm_shift))
 
+#define set_pstate_pan(x)		asm volatile(SET_PSTATE_PAN(x))
+#define set_pstate_uao(x)		asm volatile(SET_PSTATE_UAO(x))
+#define set_pstate_ssbs(x)		asm volatile(SET_PSTATE_SSBS(x))
+
 #define __SYS_BARRIER_INSN(CRm, op2, Rt) \
 	__emit_inst(0xd5000000 | sys_insn(0, 3, 3, (CRm), (op2)) | ((Rt) & 0x1f))
 

arch/arm64/kernel/cpufeature.c

···
 	WARN_ON_ONCE(in_interrupt());
 
 	sysreg_clear_set(sctlr_el1, SCTLR_EL1_SPAN, 0);
-	asm(SET_PSTATE_PAN(1));
+	set_pstate_pan(1);
 }
 #endif /* CONFIG_ARM64_PAN */
 

arch/arm64/kernel/proton-pack.c

···
 
 	if (spectre_v4_mitigations_off()) {
 		sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS);
-		asm volatile(SET_PSTATE_SSBS(1));
+		set_pstate_ssbs(1);
 		return SPECTRE_VULNERABLE;
 	}
 
 	/* SCTLR_EL1.DSSBS was initialised to 0 during boot */
-	asm volatile(SET_PSTATE_SSBS(0));
+	set_pstate_ssbs(0);
 	return SPECTRE_MITIGATED;
 }