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authorCatalin Marinas <catalin.marinas@arm.com>2009-05-30 14:00:18 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2009-05-30 14:00:18 +0100
commit85d6943af50537d3aec58b967ffbd3fec88453e9 (patch)
tree2033d95a7a57f792856cc08e1bd77f01386c5ed6 /arch/arm/vfp
parent26584853a44c58f3d6ac7360d697a2ddcd1a3efa (diff)
downloadop-kernel-dev-85d6943af50537d3aec58b967ffbd3fec88453e9.zip
op-kernel-dev-85d6943af50537d3aec58b967ffbd3fec88453e9.tar.gz
Fix the VFP handling on the Feroceon CPU
This CPU generates synchronous VFP exceptions in a non-standard way - the FPEXC.EX bit set but without the FPSCR.IXE bit being set like in the VFP subarchitecture 1 or just the FPEXC.DEX bit like in VFP subarchitecture 2. The main problem is that the faulty instruction (which needs to be emulated in software) will be restarted several times (normally until a context switch disables the VFP). This patch ensures that the VFP exception is treated as synchronous. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Nicolas Pitre <nico@cam.org>
Diffstat (limited to 'arch/arm/vfp')
-rw-r--r--arch/arm/vfp/vfphw.S4
-rw-r--r--arch/arm/vfp/vfpmodule.c2
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
index 83c4e38..1aeae38 100644
--- a/arch/arm/vfp/vfphw.S
+++ b/arch/arm/vfp/vfphw.S
@@ -100,6 +100,7 @@ ENTRY(vfp_support_entry)
beq no_old_VFP_process
VFPFSTMIA r4, r5 @ save the working registers
VFPFMRX r5, FPSCR @ current status
+#ifndef CONFIG_CPU_FEROCEON
tst r1, #FPEXC_EX @ is there additional state to save?
beq 1f
VFPFMRX r6, FPINST @ FPINST (only if FPEXC.EX is set)
@@ -107,6 +108,7 @@ ENTRY(vfp_support_entry)
beq 1f
VFPFMRX r8, FPINST2 @ FPINST2 if needed (and present)
1:
+#endif
stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
@ and point r4 at the word at the
@ start of the register dump
@@ -119,6 +121,7 @@ no_old_VFP_process:
VFPFLDMIA r10, r5 @ reload the working registers while
@ FPEXC is in a safe state
ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2
+#ifndef CONFIG_CPU_FEROCEON
tst r1, #FPEXC_EX @ is there additional state to restore?
beq 1f
VFPFMXR FPINST, r6 @ restore FPINST (only if FPEXC.EX is set)
@@ -126,6 +129,7 @@ no_old_VFP_process:
beq 1f
VFPFMXR FPINST2, r8 @ FPINST2 if needed (and present)
1:
+#endif
VFPFMXR FPSCR, r5 @ restore status
check_for_exception:
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 01599c4..2d7423a 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -253,12 +253,14 @@ void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
}
if (fpexc & FPEXC_EX) {
+#ifndef CONFIG_CPU_FEROCEON
/*
* Asynchronous exception. The instruction is read from FPINST
* and the interrupted instruction has to be restarted.
*/
trigger = fmrx(FPINST);
regs->ARM_pc -= 4;
+#endif
} else if (!(fpexc & FPEXC_DEX)) {
/*
* Illegal combination of bits. It can be caused by an
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