[PATCH 15/18] arm64: kvm: Modernize __smccc_workaround_1_smc_start annotations

From: Mark Brown <broonie@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mark Brown <broonie@kernel.org>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org,
	linux-crypto@vger.kernel.org
Subject: [PATCH 15/18] arm64: kvm: Modernize __smccc_workaround_1_smc_start annotations
Date: Tue, 18 Feb 2020 19:58:39 +0000	[thread overview]
Message-ID: <20200218195842.34156-16-broonie@kernel.org> (raw)
In-Reply-To: <20200218195842.34156-1-broonie@kernel.org>

In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These replace ENTRY and
ENDPROC with separate annotations for standard C callable functions,
data and code with different calling conventions.

Using these for __smccc_workaround_1_smc is more involved than for most
symbols as this symbol is annotated quite unusually, rather than just have
the explicit symbol we define _start and _end symbols which we then use to
compute the length. This does not play at all nicely with the new style
macros. Instead define a constant for the size of the function and use that
in both the C code and for .org based size checks in the assembly code.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/kvm_asm.h |  4 ++++
 arch/arm64/kernel/cpu_errata.c   | 14 ++++++--------
 arch/arm64/kvm/hyp/hyp-entry.S   |  6 ++++--
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 44a243754c1b..7c7eeeaab9fa 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -36,6 +36,8 @@
  */
 #define KVM_VECTOR_PREAMBLE	(2 * AARCH64_INSN_SIZE)
 
+#define __SMCCC_WORKAROUND_1_SMC_SZ 36
+
 #ifndef __ASSEMBLY__
 
 #include <linux/mm.h>
@@ -75,6 +77,8 @@ extern void __vgic_v3_init_lrs(void);
 
 extern u32 __kvm_get_mdcr_el2(void);
 
+extern char __smccc_workaround_1_smc[__SMCCC_WORKAROUND_1_SMC_SZ];
+
 /* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */
 #define __hyp_this_cpu_ptr(sym)						\
 	({								\
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 0af2201cefda..6a2ca339741c 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -11,6 +11,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/cpufeature.h>
+#include <asm/kvm_asm.h>
 #include <asm/smp_plat.h>
 
 static bool __maybe_unused
@@ -113,9 +114,6 @@ atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1);
 DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
 
 #ifdef CONFIG_KVM_INDIRECT_VECTORS
-extern char __smccc_workaround_1_smc_start[];
-extern char __smccc_workaround_1_smc_end[];
-
 static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,
 				const char *hyp_vecs_end)
 {
@@ -163,9 +161,6 @@ static void install_bp_hardening_cb(bp_hardening_cb_t fn,
 	raw_spin_unlock(&bp_lock);
 }
 #else
-#define __smccc_workaround_1_smc_start		NULL
-#define __smccc_workaround_1_smc_end		NULL
-
 static void install_bp_hardening_cb(bp_hardening_cb_t fn,
 				      const char *hyp_vecs_start,
 				      const char *hyp_vecs_end)
@@ -239,11 +234,14 @@ static int detect_harden_bp_fw(void)
 		smccc_end = NULL;
 		break;
 
+#if IS_ENABLED(CONFIG_KVM_ARM_HOST)
 	case SMCCC_CONDUIT_SMC:
 		cb = call_smc_arch_workaround_1;
-		smccc_start = __smccc_workaround_1_smc_start;
-		smccc_end = __smccc_workaround_1_smc_end;
+		smccc_start = __smccc_workaround_1_smc;
+		smccc_end = __smccc_workaround_1_smc +
+			__SMCCC_WORKAROUND_1_SMC_SZ;
 		break;
+#endif
 
 	default:
 		return -1;
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 1e2ab928a92f..c2a13ab3c471 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -322,7 +322,7 @@ SYM_CODE_END(__bp_harden_hyp_vecs)
 
 	.popsection
 
-ENTRY(__smccc_workaround_1_smc_start)
+SYM_CODE_START(__smccc_workaround_1_smc)
 	esb
 	sub	sp, sp, #(8 * 4)
 	stp	x2, x3, [sp, #(8 * 0)]
@@ -332,5 +332,7 @@ ENTRY(__smccc_workaround_1_smc_start)
 	ldp	x2, x3, [sp, #(8 * 0)]
 	ldp	x0, x1, [sp, #(8 * 2)]
 	add	sp, sp, #(8 * 4)
-ENTRY(__smccc_workaround_1_smc_end)
+1:	.org __smccc_workaround_1_smc + __SMCCC_WORKAROUND_1_SMC_SZ
+	.org 1b
+SYM_CODE_END(__smccc_workaround_1_smc)
 #endif
-- 
2.20.1

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