From: Ard Biesheuvel ardb@kernel.org
[ 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 --- 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 9a89264cdcc0b..cfedc2a3dbd68 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 26c4f61ecfa39..6d056d810e486 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