x86/boot: Move boot_*msr helpers to asm/shared/msr.h

The boot_{rdmsr,wrmsr}() helpers are *just* the barebones MSR access
functionality, without any tracing or exception handling glue as it is done in
kernel proper.

Move these helpers to asm/shared/msr.h and rename to raw_{rdmsr,wrmsr}() to
indicate what they are.

[ bp: Correct the reason why those helpers exist. I should've caught that in
the original patch that added them:
176db622573f ("x86/boot: Introduce helpers for MSR reads/writes"
but oh well...
- fixup include path delimiters to <> ]

Signed-off-by: John Allen <[e-mail]>
Signed-off-by: Borislav Petkov (AMD) <[e-mail]>
Reviewed-by: Tom Lendacky <[e-mail]>
Link: https://patch.msgid.link/all/[e-mail]

arch/x86/boot/compressed/sev.c

···
 
 #include <asm/bootparam.h>
 #include <asm/pgtable_types.h>
+#include <asm/shared/msr.h>
 #include <asm/sev.h>
 #include <asm/trapnr.h>
 #include <asm/trap_pf.h>
···
 	}
 
 	/* Set the SME mask if this is an SEV guest. */
-	boot_rdmsr(MSR_AMD64_SEV, &m);
+	raw_rdmsr(MSR_AMD64_SEV, &m);
 	sev_status = m.q;
 	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
 		return;
···
 	if (sev_check_cpu_support() < 0)
 		return 0;
 
-	boot_rdmsr(MSR_AMD64_SEV, &m);
+	raw_rdmsr(MSR_AMD64_SEV, &m);
 	return m.q;
 }
 
···
 			struct msr m;
 
 			/* Obtain the address of the calling area to use */
-			boot_rdmsr(MSR_SVSM_CAA, &m);
+			raw_rdmsr(MSR_SVSM_CAA, &m);
 			boot_svsm_caa_pa = m.q;
 
 			/*

arch/x86/boot/compressed/sev.h

···
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 
-#include "../msr.h"
+#include <asm/shared/msr.h>
 
 void snp_accept_memory(phys_addr_t start, phys_addr_t end);
 u64 sev_get_status(void);
···
 {
 	struct msr m;
 
-	boot_rdmsr(MSR_AMD64_SEV_ES_GHCB, &m);
+	raw_rdmsr(MSR_AMD64_SEV_ES_GHCB, &m);
 
 	return m.q;
 }
···
 	struct msr m;
 
 	m.q = val;
-	boot_wrmsr(MSR_AMD64_SEV_ES_GHCB, &m);
+	raw_wrmsr(MSR_AMD64_SEV_ES_GHCB, &m);
 }
 
 #else

arch/x86/boot/cpucheck.c

···
 #include <asm/intel-family.h>
 #include <asm/processor-flags.h>
 #include <asm/msr-index.h>
+#include <asm/shared/msr.h>
 
 #include "string.h"
-#include "msr.h"
 
 static u32 err_flags[NCAPINTS];
 
···
 
 		struct msr m;
 
-		boot_rdmsr(MSR_K7_HWCR, &m);
+		raw_rdmsr(MSR_K7_HWCR, &m);
 		m.l &= ~(1 << 15);
-		boot_wrmsr(MSR_K7_HWCR, &m);
+		raw_wrmsr(MSR_K7_HWCR, &m);
 
 		get_cpuflags();	/* Make sure it really did something */
 		err = check_cpuflags();
···
 
 		struct msr m;
 
-		boot_rdmsr(MSR_VIA_FCR, &m);
+		raw_rdmsr(MSR_VIA_FCR, &m);
 		m.l |= (1 << 1) | (1 << 7);
-		boot_wrmsr(MSR_VIA_FCR, &m);
+		raw_wrmsr(MSR_VIA_FCR, &m);
 
 		set_bit(X86_FEATURE_CX8, cpu.flags);
 		err = check_cpuflags();
···
 		struct msr m, m_tmp;
 		u32 level = 1;
 
-		boot_rdmsr(0x80860004, &m);
+		raw_rdmsr(0x80860004, &m);
 		m_tmp = m;
 		m_tmp.l = ~0;
-		boot_wrmsr(0x80860004, &m_tmp);
+		raw_wrmsr(0x80860004, &m_tmp);
 		asm("cpuid"
 		    : "+a" (level), "=d" (cpu.flags[0])
 		    : : "ecx", "ebx");
-		boot_wrmsr(0x80860004, &m);
+		raw_wrmsr(0x80860004, &m);
 
 		err = check_cpuflags();
 	} else if (err == 0x01 &&

arch/x86/boot/msr.h

···
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Helpers/definitions related to MSR access.
- */
-
-#ifndef BOOT_MSR_H
-#define BOOT_MSR_H
-
-#include <asm/shared/msr.h>
-
-/*
- * The kernel proper already defines rdmsr()/wrmsr(), but they are not for the
- * boot kernel since they rely on tracepoint/exception handling infrastructure
- * that's not available here.
- */
-static inline void boot_rdmsr(unsigned int reg, struct msr *m)
-{
-	asm volatile("rdmsr" : "=a" (m->l), "=d" (m->h) : "c" (reg));
-}
-
-static inline void boot_wrmsr(unsigned int reg, const struct msr *m)
-{
-	asm volatile("wrmsr" : : "c" (reg), "a"(m->l), "d" (m->h) : "memory");
-}
-
-#endif /* BOOT_MSR_H */

arch/x86/include/asm/shared/msr.h

···
 	};
 };
 
+/*
+ * The kernel proper already defines rdmsr()/wrmsr(), but they are not for the
+ * boot kernel since they rely on tracepoint/exception handling infrastructure
+ * that's not available here.
+ */
+static inline void raw_rdmsr(unsigned int reg, struct msr *m)
+{
+	asm volatile("rdmsr" : "=a" (m->l), "=d" (m->h) : "c" (reg));
+}
+
+static inline void raw_wrmsr(unsigned int reg, const struct msr *m)
+{
+	asm volatile("wrmsr" : : "c" (reg), "a"(m->l), "d" (m->h) : "memory");
+}
+
 #endif /* _ASM_X86_SHARED_MSR_H */