diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ce00c570459de45a19b0ae97c56aca85a84d36f2..7be67ef4b84f95ee5da32b86254a895fcde1f502 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -374,6 +374,14 @@ config PLAT_IOP
source arch/arm/mm/Kconfig
+config IWMMXT
+ bool "Enable iWMMXt support"
+ depends CPU_XSCALE || CPU_XSC3
+ default y if PXA27x
+ help
+ Enable support for iWMMXt context switching at run time if
+ running on a CPU that supports it.
+
# bool 'Use XScale PMU as timer source' CONFIG_XSCALE_PMU_TIMER
config XSCALE_PMU
bool
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 1320a0efca738eea92013b0d9461913d758205c7..ab06a86e85d58c71e17fb223e8e8ef4b45e22587 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -24,7 +24,9 @@ obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o
obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o
AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312
-obj-$(CONFIG_IWMMXT) += iwmmxt.o iwmmxt-notifier.o
+obj-$(CONFIG_CPU_XSCALE) += xscale-cp0.o
+obj-$(CONFIG_CPU_XSC3) += xscale-cp0.o
+obj-$(CONFIG_IWMMXT) += iwmmxt.o
AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt
ifneq ($(CONFIG_ARCH_EBSA110),y)
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index bd623b73445f79a9b37018e0da7d320d003c2a7c..2db42b18f53f060a1040ba65cf01114793535ad9 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -589,10 +589,6 @@ ENTRY(__switch_to)
strex r5, r4, [ip] @ Clear exclusive monitor
#endif
#endif
-#if defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_IWMMXT)
- mra r4, r5, acc0
- stmia ip, {r4, r5}
-#endif
#if defined(CONFIG_HAS_TLS_REG)
mcr p15, 0, r3, c13, c0, 3 @ set TLS register
#elif !defined(CONFIG_TLS_REG_EMUL)
@@ -601,11 +597,6 @@ ENTRY(__switch_to)
#endif
#ifdef CONFIG_MMU
mcr p15, 0, r6, c3, c0, 0 @ Set domain register
-#endif
-#if defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_IWMMXT)
- add r4, r2, #TI_CPU_DOMAIN + 40 @ cpu_context_save->extra
- ldmib r4, {r4, r5}
- mar acc0, r4, r5
#endif
mov r5, r0
add r4, r2, #TI_CPU_SAVE
diff --git a/arch/arm/kernel/iwmmxt-notifier.c b/arch/arm/kernel/iwmmxt-notifier.c
deleted file mode 100644
index 0d1a1db40062990a60bdd93d691a047941a6d4c1..0000000000000000000000000000000000000000
--- a/arch/arm/kernel/iwmmxt-notifier.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * linux/arch/arm/kernel/iwmmxt-notifier.c
- *
- * XScale iWMMXt (Concan) context switching and handling
- *
- * Initial code:
- * Copyright (c) 2003, Intel Corporation
- *
- * Full lazy switching support, optimizations and more, by Nicolas Pitre
- * Copyright (c) 2003-2004, MontaVista Software, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/module.h>
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <asm/thread_notify.h>
-#include <asm/io.h>
-
-static int iwmmxt_do(struct notifier_block *self, unsigned long cmd, void *t)
-{
- struct thread_info *thread = t;
-
- switch (cmd) {
- case THREAD_NOTIFY_FLUSH:
- /*
- * flush_thread() zeroes thread->fpstate, so no need
- * to do anything here.
- *
- * FALLTHROUGH: Ensure we don't try to overwrite our newly
- * initialised state information on the first fault.
- */
-
- case THREAD_NOTIFY_RELEASE:
- iwmmxt_task_release(thread);
- break;
-
- case THREAD_NOTIFY_SWITCH:
- iwmmxt_task_switch(thread);
- break;
- }
-
- return NOTIFY_DONE;
-}
-
-static struct notifier_block iwmmxt_notifier_block = {
- .notifier_call = iwmmxt_do,
-};
-
-static int __init iwmmxt_init(void)
-{
- thread_register_notifier(&iwmmxt_notifier_block);
-
- return 0;
-}
-
-late_initcall(iwmmxt_init);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 29efc9f82057c534d5ece4868e29ff00b0854e9f..6f12d2686aaf586d39aebb429a9d9138c58568b9 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -357,9 +357,6 @@ static void __init setup_processor(void)
#ifndef CONFIG_VFP
elf_hwcap &= ~HWCAP_VFP;
#endif
-#ifndef CONFIG_IWMMXT
- elf_hwcap &= ~HWCAP_IWMMXT;
-#endif
cpu_proc_init();
}
diff --git a/arch/arm/kernel/xscale-cp0.c b/arch/arm/kernel/xscale-cp0.c
new file mode 100644
index 0000000000000000000000000000000000000000..180000bfdc8fcd0e5f1ec6c54a2995e8126f3b6e
--- /dev/null
+++ b/arch/arm/kernel/xscale-cp0.c
@@ -0,0 +1,179 @@
+/*
+ * linux/arch/arm/kernel/xscale-cp0.c
+ *
+ * XScale DSP and iWMMXt coprocessor context switching and handling
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <asm/thread_notify.h>
+#include <asm/io.h>
+
+static inline void dsp_save_state(u32 *state)
+{
+ __asm__ __volatile__ (
+ "mrrc p0, 0, %0, %1, c0\n"
+ : "=r" (state[0]), "=r" (state[1]));
+}
+
+static inline void dsp_load_state(u32 *state)
+{
+ __asm__ __volatile__ (
+ "mcrr p0, 0, %0, %1, c0\n"
+ : : "r" (state[0]), "r" (state[1]));
+}
+
+static int dsp_do(struct notifier_block *self, unsigned long cmd, void *t)
+{
+ struct thread_info *thread = t;
+
+ switch (cmd) {
+ case THREAD_NOTIFY_FLUSH:
+ thread->cpu_context.extra[0] = 0;
+ thread->cpu_context.extra[1] = 0;
+ break;
+
+ case THREAD_NOTIFY_SWITCH:
+ dsp_save_state(current_thread_info()->cpu_context.extra);
+ dsp_load_state(thread->cpu_context.extra);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block dsp_notifier_block = {
+ .notifier_call = dsp_do,
+};
+
+
+#ifdef CONFIG_IWMMXT
+static int iwmmxt_do(struct notifier_block *self, unsigned long cmd, void *t)
+{
+ struct thread_info *thread = t;
+
+ switch (cmd) {
+ case THREAD_NOTIFY_FLUSH:
+ /*
+ * flush_thread() zeroes thread->fpstate, so no need
+ * to do anything here.
+ *
+ * FALLTHROUGH: Ensure we don't try to overwrite our newly
+ * initialised state information on the first fault.
+ */
+
+ case THREAD_NOTIFY_RELEASE:
+ iwmmxt_task_release(thread);
+ break;
+
+ case THREAD_NOTIFY_SWITCH:
+ iwmmxt_task_switch(thread);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block iwmmxt_notifier_block = {
+ .notifier_call = iwmmxt_do,
+};
+#endif
+
+
+static u32 __init xscale_cp_access_read(void)
+{
+ u32 value;
+
+ __asm__ __volatile__ (
+ "mrc p15, 0, %0, c15, c1, 0\n\t"
+ : "=r" (value));
+
+ return value;
+}
+
+static void __init xscale_cp_access_write(u32 value)
+{
+ u32 temp;
+
+ __asm__ __volatile__ (
+ "mcr p15, 0, %1, c15, c1, 0\n\t"
+ "mrc p15, 0, %0, c15, c1, 0\n\t"
+ "mov %0, %0\n\t"
+ "sub pc, pc, #4\n\t"
+ : "=r" (temp) : "r" (value));
+}
+
+/*
+ * Detect whether we have a MAC coprocessor (40 bit register) or an
+ * iWMMXt coprocessor (64 bit registers) by loading 00000100:00000000
+ * into a coprocessor register and reading it back, and checking
+ * whether the upper word survived intact.
+ */
+static int __init cpu_has_iwmmxt(void)
+{
+ u32 lo;
+ u32 hi;
+
+ /*
+ * This sequence is interpreted by the DSP coprocessor as:
+ * mar acc0, %2, %3
+ * mra %0, %1, acc0
+ *
+ * And by the iWMMXt coprocessor as:
+ * tmcrr wR0, %2, %3
+ * tmrrc %0, %1, wR0
+ */
+ __asm__ __volatile__ (
+ "mcrr p0, 0, %2, %3, c0\n"
+ "mrrc p0, 0, %0, %1, c0\n"
+ : "=r" (lo), "=r" (hi)
+ : "r" (0), "r" (0x100));
+
+ return !!hi;
+}
+
+
+/*
+ * If we detect that the CPU has iWMMXt (and CONFIG_IWMMXT=y), we
+ * disable CP0/CP1 on boot, and let call_fpe() and the iWMMXt lazy
+ * switch code handle iWMMXt context switching. If on the other
+ * hand the CPU has a DSP coprocessor, we keep access to CP0 enabled
+ * all the time, and save/restore acc0 on context switch in non-lazy
+ * fashion.
+ */
+static int __init xscale_cp0_init(void)
+{
+ u32 cp_access;
+
+ cp_access = xscale_cp_access_read() & ~3;
+ xscale_cp_access_write(cp_access | 1);
+
+ if (cpu_has_iwmmxt()) {
+#ifndef CONFIG_IWMMXT
+ printk(KERN_WARNING "CAUTION: XScale iWMMXt coprocessor "
+ "detected, but kernel support is missing.\n");
+#else
+ printk(KERN_INFO "XScale iWMMXt coprocessor detected.\n");
+ elf_hwcap |= HWCAP_IWMMXT;
+ thread_register_notifier(&iwmmxt_notifier_block);
+#endif
+ } else {
+ printk(KERN_INFO "XScale DSP coprocessor detected.\n");
+ thread_register_notifier(&dsp_notifier_block);
+ cp_access |= 1;
+ }
+
+ xscale_cp_access_write(cp_access);
+
+ return 0;
+}
+
+late_initcall(xscale_cp0_init);
diff --git a/arch/arm/mach-pxa/Kconfig b/arch/arm/mach-pxa/Kconfig
index 03d07cae26c827285f9407e47c9b46504d6a08b1..9e3d0bdcba071acd5e8e185aa933417367ed8d08 100644
--- a/arch/arm/mach-pxa/Kconfig
+++ b/arch/arm/mach-pxa/Kconfig
@@ -13,12 +13,10 @@ config ARCH_LUBBOCK
config MACH_LOGICPD_PXA270
bool "LogicPD PXA270 Card Engine Development Platform"
select PXA27x
- select IWMMXT
config MACH_MAINSTONE
bool "Intel HCDDBBVA0 Development Platform"
select PXA27x
- select IWMMXT
config ARCH_PXA_IDP
bool "Accelent Xscale IDP"
@@ -53,7 +51,6 @@ config PXA_SHARPSL_25x
config PXA_SHARPSL_27x
bool "Sharp PXA270 models (SL-Cxx00)"
select PXA27x
- select IWMMXT
endchoice
@@ -129,11 +126,6 @@ config PXA27x
help
Select code specific to PXA27x variants
-config IWMMXT
- bool
- help
- Enable support for iWMMXt
-
config PXA_SHARP_C7xx
bool
select PXA_SSP
diff --git a/arch/arm/mach-pxa/pm.c b/arch/arm/mach-pxa/pm.c
index 2112c414f0e212588742c1be02c2a312772856a8..b4d8276d6050b1e34d16c06153228f03c0b113a3 100644
--- a/arch/arm/mach-pxa/pm.c
+++ b/arch/arm/mach-pxa/pm.c
@@ -83,7 +83,8 @@ int pxa_pm_enter(suspend_state_t state)
#ifdef CONFIG_IWMMXT
/* force any iWMMXt context to ram **/
- iwmmxt_task_disable(NULL);
+ if (elf_hwcap & HWCAP_IWMMXT)
+ iwmmxt_task_disable(NULL);
#endif
/* preserve current time */
diff --git a/arch/arm/mm/proc-xscale.S b/arch/arm/mm/proc-xscale.S
index 906e9de7f83e827aa63e7121832ca7a6b69451f4..cc1004b3e5117cdcfa9a6d365406de93ebdb1722 100644
--- a/arch/arm/mm/proc-xscale.S
+++ b/arch/arm/mm/proc-xscale.S
@@ -491,12 +491,7 @@ __xscale_setup:
mcr p15, 0, ip, c7, c7, 0 @ invalidate I, D caches & BTB
mcr p15, 0, ip, c7, c10, 4 @ Drain Write (& Fill) Buffer
mcr p15, 0, ip, c8, c7, 0 @ invalidate I, D TLBs
-#ifdef CONFIG_IWMMXT
- mov r0, #0 @ initially disallow access to CP0/CP1
-#else
- mov r0, #1 @ Allow access to CP0
-#endif
- orr r0, r0, #1 << 6 @ cp6 for IOP3xx and Bulverde
+ mov r0, #1 << 6 @ cp6 for IOP3xx and Bulverde
orr r0, r0, #1 << 13 @ Its undefined whether this
mcr p15, 0, r0, c15, c1, 0 @ affects USR or SVC modes
@@ -909,7 +904,7 @@ __pxa270_proc_info:
b __xscale_setup
.long cpu_arch_name
.long cpu_elf_name
- .long HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_IWMMXT
+ .long HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP
.long cpu_pxa270_name
.long xscale_processor_functions
.long v4wbi_tlb_fns
diff --git a/include/asm-arm/elf.h b/include/asm-arm/elf.h
index f3929307a56b6a06fe1b95bbe2a07fed32803c69..642382d2c9f051eec79f4b13ffcfc7cbc4a42432 100644
--- a/include/asm-arm/elf.h
+++ b/include/asm-arm/elf.h
@@ -114,40 +114,24 @@ extern char elf_platform[];
have no such handler. */
#define ELF_PLAT_INIT(_r, load_addr) (_r)->ARM_r0 = 0
-#ifndef CONFIG_IWMMXT
-
-/* Old NetWinder binaries were compiled in such a way that the iBCS
- heuristic always trips on them. Until these binaries become uncommon
- enough not to care, don't trust the `ibcs' flag here. In any case
- there is no other ELF system currently supported by iBCS.
- @@ Could print a warning message to encourage users to upgrade. */
-#define SET_PERSONALITY(ex,ibcs2) \
- set_personality(((ex).e_flags & EF_ARM_APCS26 ? PER_LINUX : PER_LINUX_32BIT))
-
-#else
-
/*
- * All iWMMXt capable CPUs don't support 26-bit mode. Yet they can run
- * legacy binaries which used to contain FPA11 floating point instructions
- * that have always been emulated by the kernel. PFA11 and iWMMXt overlap
- * on coprocessor 1 space though. We therefore must decide if given task
- * is allowed to use CP 0 and 1 for iWMMXt, or if they should be blocked
- * at all times for the prefetch exception handler to catch FPA11 opcodes
- * and emulate them. The best indication to discriminate those two cases
- * is the SOFT_FLOAT flag in the ELF header.
+ * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
+ * and CP1, we only enable access to the iWMMXt coprocessor if the
+ * binary is EABI or softfloat (and thus, guaranteed not to use
+ * FPA instructions.)
*/
-
-#define SET_PERSONALITY(ex,ibcs2) \
-do { \
- set_personality(PER_LINUX_32BIT); \
- if (((ex).e_flags & EF_ARM_EABI_MASK) || \
- ((ex).e_flags & EF_ARM_SOFT_FLOAT)) \
- set_thread_flag(TIF_USING_IWMMXT); \
- else \
- clear_thread_flag(TIF_USING_IWMMXT); \
-} while (0)
-
-#endif
+#define SET_PERSONALITY(ex, ibcs2) \
+ do { \
+ if ((ex).e_flags & EF_ARM_APCS26) { \
+ set_personality(PER_LINUX); \
+ } else { \
+ set_personality(PER_LINUX_32BIT); \
+ if (elf_hwcap & HWCAP_IWMMXT && (ex).e_flags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) \
+ set_thread_flag(TIF_USING_IWMMXT); \
+ else \
+ clear_thread_flag(TIF_USING_IWMMXT); \
+ } \
+ } while (0)
#endif