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parisc: Add alternative coding infrastructure
authorHelge Deller <deller@gmx.de>
Tue, 16 Oct 2018 20:38:22 +0000 (22:38 +0200)
committerHelge Deller <deller@gmx.de>
Wed, 17 Oct 2018 15:22:26 +0000 (17:22 +0200)
This patch adds the necessary code to patch a running kernel at runtime
to improve performance.

The current implementation offers a few optimizations variants:

- When running a SMP kernel on a single UP processor, unwanted assembler
  statements like locking functions are overwritten with NOPs. When
  multiple instructions shall be skipped, one branch instruction is used
  instead of multiple nop instructions.

- In the UP case, some pdtlb and pitlb instructions are patched to
  become pdtlb,l and pitlb,l which only flushes the CPU-local tlb
  entries instead of broadcasting the flush to other CPUs in the system
  and thus may improve performance.

- fic and fdc instructions are skipped if no I- or D-caches are
  installed.  This should speed up qemu emulation and cacheless systems.

- If no cache coherence is needed for IO operations, the relevant fdc
  and sync instructions in the sba and ccio drivers are replaced by
  nops.

- On systems which share I- and D-TLBs and thus don't have a seperate
  instruction TLB, the pitlb instruction is replaced by a nop.

Live-patching is done early in the boot process, just after having run
the system inventory. No drivers are running and thus no external
interrupts should arrive. So the hope is that no TLB exceptions will
occur during the patching. If this turns out to be wrong we will
probably need to do the patching in real-mode.

Signed-off-by: Helge Deller <deller@gmx.de>
14 files changed:
arch/parisc/include/asm/alternative.h [new file with mode: 0644]
arch/parisc/include/asm/cache.h
arch/parisc/include/asm/pgtable.h
arch/parisc/include/asm/sections.h
arch/parisc/include/asm/tlbflush.h
arch/parisc/kernel/cache.c
arch/parisc/kernel/entry.S
arch/parisc/kernel/pacache.S
arch/parisc/kernel/setup.c
arch/parisc/kernel/signal.c
arch/parisc/kernel/vmlinux.lds.S
arch/parisc/mm/init.c
drivers/parisc/ccio-dma.c
drivers/parisc/sba_iommu.c

diff --git a/arch/parisc/include/asm/alternative.h b/arch/parisc/include/asm/alternative.h
new file mode 100644 (file)
index 0000000..bf485a9
--- /dev/null
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_PARISC_ALTERNATIVE_H
+#define __ASM_PARISC_ALTERNATIVE_H
+
+#define ALT_COND_NO_SMP                0x01    /* when running UP instead of SMP */
+#define ALT_COND_NO_DCACHE     0x02    /* if system has no d-cache  */
+#define ALT_COND_NO_ICACHE     0x04    /* if system has no i-cache  */
+#define ALT_COND_NO_SPLIT_TLB  0x08    /* if split_tlb == 0  */
+#define ALT_COND_NO_IOC_FDC    0x10    /* if I/O cache does not need flushes */
+
+#define INSN_PxTLB     0x02            /* modify pdtlb, pitlb */
+#define INSN_NOP       0x08000240      /* nop */
+
+#ifndef __ASSEMBLY__
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/stringify.h>
+
+struct alt_instr {
+       s32 orig_offset;        /* offset to original instructions */
+       u32 len;                /* end of original instructions */
+       u32 cond;               /* see ALT_COND_XXX */
+       u32 replacement;        /* replacement instruction or code */
+};
+
+void set_kernel_text_rw(int enable_read_write);
+
+/* Alternative SMP implementation. */
+#define ALTERNATIVE(cond, replacement)         "!0:"   \
+       ".section .altinstructions, \"aw\"      !"      \
+       ".word (0b-4-.), 1, " __stringify(cond) ","     \
+               __stringify(replacement) "      !"      \
+       ".previous"
+
+#else
+
+#define ALTERNATIVE(from, to, cond, replacement)\
+       .section .altinstructions, "aw" !       \
+       .word (from - .), (to - from)/4 !       \
+       .word cond, replacement         !       \
+       .previous
+
+#endif  /*  __ASSEMBLY__  */
+
+#endif /* __ASM_PARISC_ALTERNATIVE_H */
index 150b7f3..006fb93 100644 (file)
@@ -6,6 +6,7 @@
 #ifndef __ARCH_PARISC_CACHE_H
 #define __ARCH_PARISC_CACHE_H
 
+#include <asm/alternative.h>
 
 /*
  * PA 2.0 processors have 64 and 128-byte L2 cachelines; PA 1.1 processors
@@ -41,9 +42,24 @@ extern int icache_stride;
 extern struct pdc_cache_info cache_info;
 void parisc_setup_cache_timing(void);
 
-#define pdtlb(addr)         asm volatile("pdtlb 0(%%sr1,%0)" : : "r" (addr));
-#define pitlb(addr)         asm volatile("pitlb 0(%%sr1,%0)" : : "r" (addr));
-#define pdtlb_kernel(addr)  asm volatile("pdtlb 0(%0)" : : "r" (addr));
+#define pdtlb(addr)    asm volatile("pdtlb 0(%%sr1,%0)" \
+                       ALTERNATIVE(ALT_COND_NO_SMP, INSN_PxTLB) \
+                       : : "r" (addr))
+#define pitlb(addr)    asm volatile("pitlb 0(%%sr1,%0)" \
+                       ALTERNATIVE(ALT_COND_NO_SMP, INSN_PxTLB) \
+                       ALTERNATIVE(ALT_COND_NO_SPLIT_TLB, INSN_NOP) \
+                       : : "r" (addr))
+#define pdtlb_kernel(addr)  asm volatile("pdtlb 0(%0)"   \
+                       ALTERNATIVE(ALT_COND_NO_SMP, INSN_PxTLB) \
+                       : : "r" (addr))
+
+#define asm_io_fdc(addr) asm volatile("fdc %%r0(%0)" \
+                       ALTERNATIVE(ALT_COND_NO_DCACHE, INSN_NOP) \
+                       ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) \
+                       : : "r" (addr))
+#define asm_io_sync()  asm volatile("sync" \
+                       ALTERNATIVE(ALT_COND_NO_DCACHE, INSN_NOP) \
+                       ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) :: )
 
 #endif /* ! __ASSEMBLY__ */
 
index b86c312..94c0ef7 100644 (file)
@@ -43,8 +43,7 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 {
        mtsp(mm->context, 1);
        pdtlb(addr);
-       if (unlikely(split_tlb))
-               pitlb(addr);
+       pitlb(addr);
 }
 
 /* Certain architectures need to do special things when PTEs
index 5a40b51..bb52aea 100644 (file)
@@ -5,6 +5,8 @@
 /* nothing to see, move along */
 #include <asm-generic/sections.h>
 
+extern char __alt_instructions[], __alt_instructions_end[];
+
 #ifdef CONFIG_64BIT
 
 #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
index 14668bd..6804374 100644 (file)
@@ -85,8 +85,7 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
        purge_tlb_start(flags);
        mtsp(sid, 1);
        pdtlb(addr);
-       if (unlikely(split_tlb))
-               pitlb(addr);
+       pitlb(addr);
        purge_tlb_end(flags);
 }
 #endif
index 9f1c29d..56dc979 100644 (file)
@@ -479,18 +479,6 @@ int __flush_tlb_range(unsigned long sid, unsigned long start,
        /* Purge TLB entries for small ranges using the pdtlb and
           pitlb instructions.  These instructions execute locally
           but cause a purge request to be broadcast to other TLBs.  */
-       if (likely(!split_tlb)) {
-               while (start < end) {
-                       purge_tlb_start(flags);
-                       mtsp(sid, 1);
-                       pdtlb(start);
-                       purge_tlb_end(flags);
-                       start += PAGE_SIZE;
-               }
-               return 0;
-       }
-
-       /* split TLB case */
        while (start < end) {
                purge_tlb_start(flags);
                mtsp(sid, 1);
index 7c85a91..d3e2633 100644 (file)
@@ -38,6 +38,7 @@
 #include <asm/ldcw.h>
 #include <asm/traps.h>
 #include <asm/thread_info.h>
+#include <asm/alternative.h>
 
 #include <linux/linkage.h>
 
        /* Acquire pa_tlb_lock lock and check page is present. */
        .macro          tlb_lock        spc,ptp,pte,tmp,tmp1,fault
 #ifdef CONFIG_SMP
-       cmpib,COND(=),n 0,\spc,2f
+98:    cmpib,COND(=),n 0,\spc,2f
        load_pa_tlb_lock \tmp
 1:     LDCW            0(\tmp),\tmp1
        cmpib,COND(=)   0,\tmp1,1b
        bb,<,n          \pte,_PAGE_PRESENT_BIT,3f
        b               \fault
        stw,ma          \spc,0(\tmp)
+99:    ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
 #endif
 2:     LDREG           0(\ptp),\pte
        bb,>=,n         \pte,_PAGE_PRESENT_BIT,\fault
        /* Release pa_tlb_lock lock without reloading lock address. */
        .macro          tlb_unlock0     spc,tmp
 #ifdef CONFIG_SMP
-       or,COND(=)      %r0,\spc,%r0
+98:    or,COND(=)      %r0,\spc,%r0
        stw,ma          \spc,0(\tmp)
+99:    ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
 #endif
        .endm
 
        /* Release pa_tlb_lock lock. */
        .macro          tlb_unlock1     spc,tmp
 #ifdef CONFIG_SMP
-       load_pa_tlb_lock \tmp
+98:    load_pa_tlb_lock \tmp
+99:    ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
        tlb_unlock0     \spc,\tmp
 #endif
        .endm
index f33bf2d..b41c013 100644 (file)
@@ -37,6 +37,7 @@
 #include <asm/pgtable.h>
 #include <asm/cache.h>
 #include <asm/ldcw.h>
+#include <asm/alternative.h>
 #include <linux/linkage.h>
 #include <linux/init.h>
 
@@ -190,7 +191,7 @@ ENDPROC_CFI(flush_tlb_all_local)
        .import cache_info,data
 
 ENTRY_CFI(flush_instruction_cache_local)
-       load32          cache_info, %r1
+88:    load32          cache_info, %r1
 
        /* Flush Instruction Cache */
 
@@ -243,6 +244,7 @@ fioneloop2:
 fisync:
        sync
        mtsm            %r22                    /* restore I-bit */
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_instruction_cache_local)
@@ -250,7 +252,7 @@ ENDPROC_CFI(flush_instruction_cache_local)
 
        .import cache_info, data
 ENTRY_CFI(flush_data_cache_local)
-       load32          cache_info, %r1
+88:    load32          cache_info, %r1
 
        /* Flush Data Cache */
 
@@ -304,6 +306,7 @@ fdsync:
        syncdma
        sync
        mtsm            %r22                    /* restore I-bit */
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_data_cache_local)
@@ -312,6 +315,7 @@ ENDPROC_CFI(flush_data_cache_local)
 
        .macro  tlb_lock        la,flags,tmp
 #ifdef CONFIG_SMP
+98:
 #if __PA_LDCW_ALIGNMENT > 4
        load32          pa_tlb_lock + __PA_LDCW_ALIGNMENT-1, \la
        depi            0,31,__PA_LDCW_ALIGN_ORDER, \la
@@ -326,15 +330,17 @@ ENDPROC_CFI(flush_data_cache_local)
        nop
        b,n             2b
 3:
+99:    ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
 #endif
        .endm
 
        .macro  tlb_unlock      la,flags,tmp
 #ifdef CONFIG_SMP
-       ldi             1,\tmp
+98:    ldi             1,\tmp
        sync
        stw             \tmp,0(\la)
        mtsm            \flags
+99:    ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
 #endif
        .endm
 
@@ -596,9 +602,11 @@ ENTRY_CFI(copy_user_page_asm)
        pdtlb,l         %r0(%r29)
 #else
        tlb_lock        %r20,%r21,%r22
-       pdtlb           %r0(%r28)
-       pdtlb           %r0(%r29)
+0:     pdtlb           %r0(%r28)
+1:     pdtlb           %r0(%r29)
        tlb_unlock      %r20,%r21,%r22
+       ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
+       ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif
 
 #ifdef CONFIG_64BIT
@@ -736,8 +744,9 @@ ENTRY_CFI(clear_user_page_asm)
        pdtlb,l         %r0(%r28)
 #else
        tlb_lock        %r20,%r21,%r22
-       pdtlb           %r0(%r28)
+0:     pdtlb           %r0(%r28)
        tlb_unlock      %r20,%r21,%r22
+       ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif
 
 #ifdef CONFIG_64BIT
@@ -813,11 +822,12 @@ ENTRY_CFI(flush_dcache_page_asm)
        pdtlb,l         %r0(%r28)
 #else
        tlb_lock        %r20,%r21,%r22
-       pdtlb           %r0(%r28)
+0:     pdtlb           %r0(%r28)
        tlb_unlock      %r20,%r21,%r22
+       ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif
 
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), r31
 
 #ifdef CONFIG_64BIT
@@ -847,6 +857,7 @@ ENTRY_CFI(flush_dcache_page_asm)
        cmpb,COND(<<)   %r28, %r25,1b
        fdc,m           r31(%r28)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
@@ -874,15 +885,19 @@ ENTRY_CFI(flush_icache_page_asm)
 
 #ifdef CONFIG_PA20
        pdtlb,l         %r0(%r28)
-       pitlb,l         %r0(%sr4,%r28)
+1:     pitlb,l         %r0(%sr4,%r28)
+       ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)
 #else
        tlb_lock        %r20,%r21,%r22
-       pdtlb           %r0(%r28)
-       pitlb           %r0(%sr4,%r28)
+0:     pdtlb           %r0(%r28)
+1:     pitlb           %r0(%sr4,%r28)
        tlb_unlock      %r20,%r21,%r22
+       ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
+       ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
+       ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)
 #endif
 
-       ldil            L%icache_stride, %r1
+88:    ldil            L%icache_stride, %r1
        ldw             R%icache_stride(%r1), %r31
 
 #ifdef CONFIG_64BIT
@@ -914,13 +929,14 @@ ENTRY_CFI(flush_icache_page_asm)
        cmpb,COND(<<)   %r28, %r25,1b
        fic,m           %r31(%sr4,%r28)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_icache_page_asm)
 
 ENTRY_CFI(flush_kernel_dcache_page_asm)
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), %r23
 
 #ifdef CONFIG_64BIT
@@ -950,13 +966,14 @@ ENTRY_CFI(flush_kernel_dcache_page_asm)
        cmpb,COND(<<)           %r26, %r25,1b
        fdc,m           %r23(%r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_kernel_dcache_page_asm)
 
 ENTRY_CFI(purge_kernel_dcache_page_asm)
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), %r23
 
 #ifdef CONFIG_64BIT
@@ -985,13 +1002,14 @@ ENTRY_CFI(purge_kernel_dcache_page_asm)
        cmpb,COND(<<)           %r26, %r25, 1b
        pdc,m           %r23(%r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(purge_kernel_dcache_page_asm)
 
 ENTRY_CFI(flush_user_dcache_range_asm)
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), %r23
        ldo             -1(%r23), %r21
        ANDCM           %r26, %r21, %r26
@@ -999,13 +1017,14 @@ ENTRY_CFI(flush_user_dcache_range_asm)
 1:      cmpb,COND(<<),n        %r26, %r25, 1b
        fdc,m           %r23(%sr3, %r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_user_dcache_range_asm)
 
 ENTRY_CFI(flush_kernel_dcache_range_asm)
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), %r23
        ldo             -1(%r23), %r21
        ANDCM           %r26, %r21, %r26
@@ -1014,13 +1033,14 @@ ENTRY_CFI(flush_kernel_dcache_range_asm)
        fdc,m           %r23(%r26)
 
        sync
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        syncdma
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_kernel_dcache_range_asm)
 
 ENTRY_CFI(purge_kernel_dcache_range_asm)
-       ldil            L%dcache_stride, %r1
+88:    ldil            L%dcache_stride, %r1
        ldw             R%dcache_stride(%r1), %r23
        ldo             -1(%r23), %r21
        ANDCM           %r26, %r21, %r26
@@ -1029,13 +1049,14 @@ ENTRY_CFI(purge_kernel_dcache_range_asm)
        pdc,m           %r23(%r26)
 
        sync
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_DCACHE, INSN_NOP)
        syncdma
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(purge_kernel_dcache_range_asm)
 
 ENTRY_CFI(flush_user_icache_range_asm)
-       ldil            L%icache_stride, %r1
+88:    ldil            L%icache_stride, %r1
        ldw             R%icache_stride(%r1), %r23
        ldo             -1(%r23), %r21
        ANDCM           %r26, %r21, %r26
@@ -1043,13 +1064,14 @@ ENTRY_CFI(flush_user_icache_range_asm)
 1:      cmpb,COND(<<),n        %r26, %r25,1b
        fic,m           %r23(%sr3, %r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_user_icache_range_asm)
 
 ENTRY_CFI(flush_kernel_icache_page)
-       ldil            L%icache_stride, %r1
+88:    ldil            L%icache_stride, %r1
        ldw             R%icache_stride(%r1), %r23
 
 #ifdef CONFIG_64BIT
@@ -1079,13 +1101,14 @@ ENTRY_CFI(flush_kernel_icache_page)
        cmpb,COND(<<)           %r26, %r25, 1b
        fic,m           %r23(%sr4, %r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
 ENDPROC_CFI(flush_kernel_icache_page)
 
 ENTRY_CFI(flush_kernel_icache_range_asm)
-       ldil            L%icache_stride, %r1
+88:    ldil            L%icache_stride, %r1
        ldw             R%icache_stride(%r1), %r23
        ldo             -1(%r23), %r21
        ANDCM           %r26, %r21, %r26
@@ -1093,6 +1116,7 @@ ENTRY_CFI(flush_kernel_icache_range_asm)
 1:      cmpb,COND(<<),n        %r26, %r25, 1b
        fic,m           %r23(%sr4, %r26)
 
+89:    ALTERNATIVE(88b, 89b, ALT_COND_NO_ICACHE, INSN_NOP)
        sync
        bv              %r0(%r2)
        nop
index 4e87c35..db6e795 100644 (file)
@@ -305,6 +305,86 @@ static int __init parisc_init_resources(void)
        return 0;
 }
 
+static int no_alternatives __initdata;
+static int __init setup_no_alternatives(char *str)
+{
+       no_alternatives = 1;
+       return 1;
+}
+__setup("no-alternatives", setup_no_alternatives);
+
+static void __init apply_alternatives_all(void)
+{
+       struct alt_instr *entry;
+       int index = 0, applied = 0;
+
+
+       pr_info("alternatives: %spatching kernel code\n",
+               no_alternatives ? "NOT " : "");
+       if (no_alternatives)
+               return;
+
+       set_kernel_text_rw(1);
+
+       for (entry = (struct alt_instr *) &__alt_instructions;
+               entry < (struct alt_instr *) &__alt_instructions_end;
+               entry++, index++) {
+
+               u32 *from, len, cond, replacement;
+
+               from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
+               len = entry->len;
+               cond = entry->cond;
+               replacement = entry->replacement;
+
+               WARN_ON(!cond);
+               pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
+                       index, cond, len, from, replacement);
+
+               if ((cond & ALT_COND_NO_SMP) && (num_online_cpus() != 1))
+                       continue;
+               if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0))
+                       continue;
+               if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0))
+                       continue;
+
+               /*
+                * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
+                * set (bit #61, big endian), we have to flush and sync every
+                * time IO-PDIR is changed in Ike/Astro.
+                */
+               if ((cond & ALT_COND_NO_IOC_FDC) &&
+                       (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC))
+                       continue;
+
+               /* Want to replace pdtlb by a pdtlb,l instruction? */
+               if (replacement == INSN_PxTLB) {
+                       replacement = *from;
+                       if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
+                               replacement |= (1 << 10); /* set el bit */
+               }
+
+               /*
+                * Replace instruction with NOPs?
+                * For long distance insert a branch instruction instead.
+                */
+               if (replacement == INSN_NOP && len > 1)
+                       replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
+
+               pr_debug("Do    %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
+                       index, cond, len, from, replacement);
+
+               /* Replace instruction */
+               *from = replacement;
+               applied++;
+       }
+
+       pr_info("alternatives: applied %d out of %d patches\n", applied, index);
+
+       set_kernel_text_rw(0);
+}
+
+
 extern void gsc_init(void);
 extern void processor_init(void);
 extern void ccio_init(void);
@@ -346,6 +426,7 @@ static int __init parisc_init(void)
                        boot_cpu_data.cpu_hz / 1000000,
                        boot_cpu_data.cpu_hz % 1000000  );
 
+       apply_alternatives_all();
        parisc_setup_cache_timing();
 
        /* These are in a non-obvious order, will fix when we have an iotree */
index 342073f..848c193 100644 (file)
@@ -65,7 +65,6 @@
 #define INSN_LDI_R25_1  0x34190002 /* ldi  1,%r25 (in_syscall=1) */
 #define INSN_LDI_R20    0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
 #define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
-#define INSN_NOP        0x08000240 /* nop */
 /* For debugging */
 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
 
index da2e311..c3b1b9c 100644 (file)
@@ -61,6 +61,12 @@ SECTIONS
                EXIT_DATA
        }
        PERCPU_SECTION(8)
+       . = ALIGN(4);
+       .altinstructions : {
+               __alt_instructions = .;
+               *(.altinstructions)
+               __alt_instructions_end = .;
+       }
        . = ALIGN(HUGEPAGE_SIZE);
        __init_end = .;
        /* freed after init ends here */
index aae9b0d..e7e626b 100644 (file)
@@ -511,6 +511,21 @@ static void __init map_pages(unsigned long start_vaddr,
        }
 }
 
+void __init set_kernel_text_rw(int enable_read_write)
+{
+       unsigned long start = (unsigned long)_stext;
+       unsigned long end   = (unsigned long)_etext;
+
+       map_pages(start, __pa(start), end-start,
+               PAGE_KERNEL_RWX, enable_read_write ? 1:0);
+
+       /* force the kernel to see the new TLB entries */
+       __flush_tlb_range(0, start, end);
+
+       /* dump old cached instructions */
+       flush_icache_range(start, end);
+}
+
 void __ref free_initmem(void)
 {
        unsigned long init_begin = (unsigned long)__init_begin;
index 6148236..701a7d6 100644 (file)
@@ -609,14 +609,13 @@ ccio_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
        **        PCX-T'? Don't know. (eg C110 or similar K-class)
        **
        ** See PDC_MODEL/option 0/SW_CAP word for "Non-coherent IO-PDIR bit".
-       ** Hopefully we can patch (NOP) these out at boot time somehow.
        **
        ** "Since PCX-U employs an offset hash that is incompatible with
        ** the real mode coherence index generation of U2, the PDIR entry
        ** must be flushed to memory to retain coherence."
        */
-       asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr));
-       asm volatile("sync");
+       asm_io_fdc(pdir_ptr);
+       asm_io_sync();
 }
 
 /**
@@ -682,17 +681,14 @@ ccio_mark_invalid(struct ioc *ioc, dma_addr_t iova, size_t byte_cnt)
                ** FIXME: PCX_W platforms don't need FDC/SYNC. (eg C360)
                **   PCX-U/U+ do. (eg C200/C240)
                ** See PDC_MODEL/option 0/SW_CAP for "Non-coherent IO-PDIR bit".
-               **
-               ** Hopefully someone figures out how to patch (NOP) the
-               ** FDC/SYNC out at boot time.
                */
-               asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr[7]));
+               asm_io_fdc(pdir_ptr);
 
                iovp     += IOVP_SIZE;
                byte_cnt -= IOVP_SIZE;
        }
 
-       asm volatile("sync");
+       asm_io_sync();
        ccio_clear_io_tlb(ioc, CCIO_IOVP(iova), saved_byte_cnt);
 }
 
index 11de0ec..c1e599a 100644 (file)
@@ -587,8 +587,7 @@ sba_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
         * (bit #61, big endian), we have to flush and sync every time
         * IO-PDIR is changed in Ike/Astro.
         */
-       if (ioc_needs_fdc)
-               asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr));
+       asm_io_fdc(pdir_ptr);
 }
 
 
@@ -641,8 +640,8 @@ sba_mark_invalid(struct ioc *ioc, dma_addr_t iova, size_t byte_cnt)
                do {
                        /* clear I/O Pdir entry "valid" bit first */
                        ((u8 *) pdir_ptr)[7] = 0;
+                       asm_io_fdc(pdir_ptr);
                        if (ioc_needs_fdc) {
-                               asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr));
 #if 0
                                entries_per_cacheline = L1_CACHE_SHIFT - 3;
 #endif
@@ -661,8 +660,7 @@ sba_mark_invalid(struct ioc *ioc, dma_addr_t iova, size_t byte_cnt)
        ** could dump core on HPMC.
        */
        ((u8 *) pdir_ptr)[7] = 0;
-       if (ioc_needs_fdc)
-               asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr));
+       asm_io_fdc(pdir_ptr);
 
        WRITE_REG( SBA_IOVA(ioc, iovp, 0, 0), ioc->ioc_hpa+IOC_PCOM);
 }
@@ -773,8 +771,7 @@ sba_map_single(struct device *dev, void *addr, size_t size,
        }
 
        /* force FDC ops in io_pdir_entry() to be visible to IOMMU */
-       if (ioc_needs_fdc)
-               asm volatile("sync" : : );
+       asm_io_sync();
 
 #ifdef ASSERT_PDIR_SANITY
        sba_check_pdir(ioc,"Check after sba_map_single()");
@@ -858,8 +855,7 @@ sba_unmap_page(struct device *dev, dma_addr_t iova, size_t size,
        sba_free_range(ioc, iova, size);
 
        /* If fdc's were issued, force fdc's to be visible now */
-       if (ioc_needs_fdc)
-               asm volatile("sync" : : );
+       asm_io_sync();
 
        READ_REG(ioc->ioc_hpa+IOC_PCOM);        /* flush purges */
 #endif /* DELAYED_RESOURCE_CNT == 0 */
@@ -1008,8 +1004,7 @@ sba_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
        filled = iommu_fill_pdir(ioc, sglist, nents, 0, sba_io_pdir_entry);
 
        /* force FDC ops in io_pdir_entry() to be visible to IOMMU */
-       if (ioc_needs_fdc)
-               asm volatile("sync" : : );
+       asm_io_sync();
 
 #ifdef ASSERT_PDIR_SANITY
        if (sba_check_pdir(ioc,"Check after sba_map_sg()"))