linux-kernel - [kvm-unit-tests PATCH v2 3/4] arm: fpu: Add '.arch

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Message-ID: <20241023152638.3317648-4-rananta@google.com>
Date: Wed, 23 Oct 2024 15:26:37 +0000
From: Raghavendra Rao Ananta <rananta@...gle.com>
To: Subhasish Ghosh <subhasish.ghosh@....com>, Joey Gouly <joey.gouly@....com>, 
	Andrew Jones <andrew.jones@...ux.dev>
Cc: Oliver Upton <oliver.upton@...ux.dev>, Marc Zyngier <maz@...nel.org>, 
	Raghavendra Rao Anata <rananta@...gle.com>, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [kvm-unit-tests PATCH v2 3/4] arm: fpu: Add '.arch_extension fp' to
 fpu macros

Since the tests are built with '-mgeneral-regs-only', clang-18 tends to
push 'q' registers out of the scope and hence, the following error is
observed:

arm/fpu.c:281:3: error: instruction requires: fp-armv8
  281 |                 fpu_reg_write(*indata);
      |                 ^
arm/fpu.c:74:15: note: expanded from macro 'fpu_reg_write'
   74 |         asm volatile("ldp q0, q1, [%0], #32\n\t"        \
      |                      ^
<inline asm>:1:2: note: instantiated into assembly here
    1 |         ldp q0, q1, [x8], #32
      |         ^

Hence, explicitly add fp support where these registers are used.

Reported-by: Andrew Jones <andrew.jones@...ux.dev>
Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
---
 arm/fpu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arm/fpu.c b/arm/fpu.c
index 587b6ea3..f327a349 100644
--- a/arm/fpu.c
+++ b/arm/fpu.c
@@ -38,7 +38,8 @@ static inline bool arch_collect_entropy(uint64_t *random)
 #define fpu_reg_read(val)				\
 ({							\
 	uint64_t *__val = (val);			\
-	asm volatile("stp q0, q1, [%0], #32\n\t"	\
+	asm volatile(".arch_extension fp\n"		\
+		     "stp q0, q1, [%0], #32\n\t"	\
 		     "stp q2, q3, [%0], #32\n\t"	\
 		     "stp q4, q5, [%0], #32\n\t"	\
 		     "stp q6, q7, [%0], #32\n\t"	\
@@ -71,7 +72,8 @@ static inline bool arch_collect_entropy(uint64_t *random)
 #define fpu_reg_write(val)				\
 do {							\
 	uint64_t *__val = (val);			\
-	asm volatile("ldp q0, q1, [%0], #32\n\t"	\
+	asm volatile(".arch_extension fp\n"		\
+		     "ldp q0, q1, [%0], #32\n\t"	\
 		     "ldp q2, q3, [%0], #32\n\t"	\
 		     "ldp q4, q5, [%0], #32\n\t"	\
 		     "ldp q6, q7, [%0], #32\n\t"	\
-- 
2.47.0.105.g07ac214952-goog