From: Ard Biesheuvel <ardb@kernel.org>
Date: Tue, 21 Mar 2023 12:01:02 +0100
Subject: [PATCH] ARM: 9292/1: vfp: Pass thread_info pointer to
vfp_support_entry
References: bsc#1012628
Patch-mainline: 6.3.2
Git-commit: dae904d96ad6a5fa79bd9d99a3decf93685d398b
[ Upstream commit dae904d96ad6a5fa79bd9d99a3decf93685d398b ]
Instead of dereferencing thread_info in do_vfp, pass the thread_info
pointer to vfp_support_entry via R1. That way, we only use a single
caller save register, which makes it easier to convert do_vfp to C code
in a subsequent patch.
Note that, unlike the CPU number, which can change due to preemption,
passing the thread_info pointer can safely be done with preemption
enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Stable-dep-of: c76c6c4ecbec ("ARM: 9294/2: vfp: Fix broken softirq handling with instrumentation enabled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
arch/arm/vfp/entry.S | 5 +----
arch/arm/vfp/vfphw.S | 10 +++++++---
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/arm/vfp/entry.S b/arch/arm/vfp/entry.S
index 9a89264c..cfedc2a3 100644
--- a/arch/arm/vfp/entry.S
+++ b/arch/arm/vfp/entry.S
@@ -22,15 +22,12 @@
@ IRQs enabled.
@
ENTRY(do_vfp)
- local_bh_disable r10, r4
+ mov r1, r10
ldr r4, .LCvfp
- ldr r11, [r10, #TI_CPU] @ CPU number
- add r10, r10, #TI_VFPSTATE @ r10 = workspace
ldr pc, [r4] @ call VFP entry point
ENDPROC(do_vfp)
ENTRY(vfp_null_entry)
- local_bh_enable_ti r10, r4
ret lr
ENDPROC(vfp_null_entry)
diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
index 26c4f61e..6d056d81 100644
--- a/arch/arm/vfp/vfphw.S
+++ b/arch/arm/vfp/vfphw.S
@@ -6,9 +6,9 @@
* Written by Deep Blue Solutions Limited.
*
* This code is called from the kernel's undefined instruction trap.
+ * r1 holds the thread_info pointer
* r9 holds the return address for successful handling.
* lr holds the return address for unrecognised instructions.
- * r10 points at the start of the private FP workspace in the thread structure
* sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h)
*/
#include <linux/init.h>
@@ -69,13 +69,17 @@
@ VFP hardware support entry point.
@
@ r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
+@ r1 = thread_info pointer
@ r2 = PC value to resume execution after successful emulation
@ r9 = normal "successful" return address
-@ r10 = vfp_state union
-@ r11 = CPU number
@ lr = unrecognised instruction return address
@ IRQs enabled.
ENTRY(vfp_support_entry)
+ local_bh_disable r1, r4
+
+ ldr r11, [r1, #TI_CPU] @ CPU number
+ add r10, r1, #TI_VFPSTATE @ r10 = workspace
+
DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
.fpu vfpv2
--
2.35.3