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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)
downloadlinux-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 83c4e384b16d..1aeae38725dd 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 01599c4ef726..2d7423af1197 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