[PATCH v4 06/11] x86/boot: Drop RIP_REL_REF() uses from SME startup code

From: Ard Biesheuvel
Date: Thu Apr 10 2025 - 09:45:22 EST


From: Ard Biesheuvel <ardb@xxxxxxxxxx>

RIP_REL_REF() has no effect on code residing in arch/x86/boot/startup,
as it is built with -fPIC. So remove any occurrences from the SME
startup code.

Note the SME is the only caller of cc_set_mask() that requires this, so
drop it from there as well.

Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/x86/boot/startup/sme.c | 11 +++++------
arch/x86/include/asm/coco.h | 2 +-
arch/x86/include/asm/mem_encrypt.h | 2 +-
3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index 23d10cda5b58..5738b31c8e60 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c
@@ -297,8 +297,7 @@ void __head sme_encrypt_kernel(struct boot_params *bp)
* instrumentation or checking boot_cpu_data in the cc_platform_has()
* function.
*/
- if (!sme_get_me_mask() ||
- RIP_REL_REF(sev_status) & MSR_AMD64_SEV_ENABLED)
+ if (!sme_get_me_mask() || sev_status & MSR_AMD64_SEV_ENABLED)
return;

/*
@@ -524,7 +523,7 @@ void __head sme_enable(struct boot_params *bp)
me_mask = 1UL << (ebx & 0x3f);

/* Check the SEV MSR whether SEV or SME is enabled */
- RIP_REL_REF(sev_status) = msr = __rdmsr(MSR_AMD64_SEV);
+ sev_status = msr = __rdmsr(MSR_AMD64_SEV);
feature_mask = (msr & MSR_AMD64_SEV_ENABLED) ? AMD_SEV_BIT : AMD_SME_BIT;

/*
@@ -560,8 +559,8 @@ void __head sme_enable(struct boot_params *bp)
return;
}

- RIP_REL_REF(sme_me_mask) = me_mask;
- RIP_REL_REF(physical_mask) &= ~me_mask;
- RIP_REL_REF(cc_vendor) = CC_VENDOR_AMD;
+ sme_me_mask = me_mask;
+ physical_mask &= ~me_mask;
+ cc_vendor = CC_VENDOR_AMD;
cc_set_mask(me_mask);
}
diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h
index e7225452963f..e1dbf8df1b69 100644
--- a/arch/x86/include/asm/coco.h
+++ b/arch/x86/include/asm/coco.h
@@ -22,7 +22,7 @@ static inline u64 cc_get_mask(void)

static inline void cc_set_mask(u64 mask)
{
- RIP_REL_REF(cc_mask) = mask;
+ cc_mask = mask;
}

u64 cc_mkenc(u64 val);
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 1530ee301dfe..ea6494628cb0 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -61,7 +61,7 @@ void __init sev_es_init_vc_handling(void);

static inline u64 sme_get_me_mask(void)
{
- return RIP_REL_REF(sme_me_mask);
+ return sme_me_mask;
}

#define __bss_decrypted __section(".bss..decrypted")
--
2.49.0.504.g3bcea36a83-goog