MIPS: MT: Remove SMTC support
Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.
Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 88e30d5..fb2d174 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -1014,19 +1014,8 @@
#define write_c0_compare3(val) __write_32bit_c0_register($11, 7, val)
#define read_c0_status() __read_32bit_c0_register($12, 0)
-#ifdef CONFIG_MIPS_MT_SMTC
-#define write_c0_status(val) \
-do { \
- __write_32bit_c0_register($12, 0, val); \
- __ehb(); \
-} while (0)
-#else
-/*
- * Legacy non-SMTC code, which may be hazardous
- * but which might not support EHB
- */
+
#define write_c0_status(val) __write_32bit_c0_register($12, 0, val)
-#endif /* CONFIG_MIPS_MT_SMTC */
#define read_c0_cause() __read_32bit_c0_register($13, 0)
#define write_c0_cause(val) __write_32bit_c0_register($13, 0, val)
@@ -1750,11 +1739,6 @@
/*
* Manipulate bits in a c0 register.
*/
-#ifndef CONFIG_MIPS_MT_SMTC
-/*
- * SMTC Linux requires shutting-down microthread scheduling
- * during CP0 register read-modify-write sequences.
- */
#define __BUILD_SET_C0(name) \
static inline unsigned int \
set_c0_##name(unsigned int set) \
@@ -1793,121 +1777,6 @@
return res; \
}
-#else /* SMTC versions that manage MT scheduling */
-
-#include <linux/irqflags.h>
-
-/*
- * This is a duplicate of dmt() in mipsmtregs.h to avoid problems with
- * header file recursion.
- */
-static inline unsigned int __dmt(void)
-{
- int res;
-
- __asm__ __volatile__(
- " .set push \n"
- " .set mips32r2 \n"
- " .set noat \n"
- " .word 0x41610BC1 # dmt $1 \n"
- " ehb \n"
- " move %0, $1 \n"
- " .set pop \n"
- : "=r" (res));
-
- instruction_hazard();
-
- return res;
-}
-
-#define __VPECONTROL_TE_SHIFT 15
-#define __VPECONTROL_TE (1UL << __VPECONTROL_TE_SHIFT)
-
-#define __EMT_ENABLE __VPECONTROL_TE
-
-static inline void __emt(unsigned int previous)
-{
- if ((previous & __EMT_ENABLE))
- __asm__ __volatile__(
- " .set mips32r2 \n"
- " .word 0x41600be1 # emt \n"
- " ehb \n"
- " .set mips0 \n");
-}
-
-static inline void __ehb(void)
-{
- __asm__ __volatile__(
- " .set mips32r2 \n"
- " ehb \n" " .set mips0 \n");
-}
-
-/*
- * Note that local_irq_save/restore affect TC-specific IXMT state,
- * not Status.IE as in non-SMTC kernel.
- */
-
-#define __BUILD_SET_C0(name) \
-static inline unsigned int \
-set_c0_##name(unsigned int set) \
-{ \
- unsigned int res; \
- unsigned int new; \
- unsigned int omt; \
- unsigned long flags; \
- \
- local_irq_save(flags); \
- omt = __dmt(); \
- res = read_c0_##name(); \
- new = res | set; \
- write_c0_##name(new); \
- __emt(omt); \
- local_irq_restore(flags); \
- \
- return res; \
-} \
- \
-static inline unsigned int \
-clear_c0_##name(unsigned int clear) \
-{ \
- unsigned int res; \
- unsigned int new; \
- unsigned int omt; \
- unsigned long flags; \
- \
- local_irq_save(flags); \
- omt = __dmt(); \
- res = read_c0_##name(); \
- new = res & ~clear; \
- write_c0_##name(new); \
- __emt(omt); \
- local_irq_restore(flags); \
- \
- return res; \
-} \
- \
-static inline unsigned int \
-change_c0_##name(unsigned int change, unsigned int newbits) \
-{ \
- unsigned int res; \
- unsigned int new; \
- unsigned int omt; \
- unsigned long flags; \
- \
- local_irq_save(flags); \
- \
- omt = __dmt(); \
- res = read_c0_##name(); \
- new = res & ~change; \
- new |= (newbits & change); \
- write_c0_##name(new); \
- __emt(omt); \
- local_irq_restore(flags); \
- \
- return res; \
-}
-#endif
-
__BUILD_SET_C0(status)
__BUILD_SET_C0(cause)
__BUILD_SET_C0(config)