[PATCH] powerpc: Separate usage of KERNELBASE and PAGE_OFFSET

This patch separates usage of KERNELBASE and PAGE_OFFSET. I haven't
looked at any of the PPC32 code, if we ever want to support Kdump on
PPC we'll have to do another audit, ditto for iSeries.

This patch makes PAGE_OFFSET the constant, it'll always be 0xC * 1
gazillion for 64-bit.

To get a physical address from a virtual one you subtract PAGE_OFFSET,
_not_ KERNELBASE.

KERNELBASE is the virtual address of the start of the kernel, it's
often the same as PAGE_OFFSET, but _might not be_.

If you want to know something's offset from the start of the kernel
you should subtract KERNELBASE.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/btext.c b/arch/powerpc/kernel/btext.c
index 893dd24..5de0d80 100644 (file)
--- a/arch/powerpc/kernel/btext.c
+++ b/arch/powerpc/kernel/btext.c
@@ -60,7 +60,7 @@ int force_printk_to_btext = 0;
  *
  * The display is mapped to virtual address 0xD0000000, rather
  * than 1:1, because some some CHRP machines put the frame buffer
- * in the region starting at 0xC0000000 (KERNELBASE).
+ * in the region starting at 0xC0000000 (PAGE_OFFSET).
  * This mapping is temporary and will disappear as soon as the
  * setup done by MMU_Init() is applied.
  *
@@ -71,7 +71,7 @@ int force_printk_to_btext = 0;
  */
 void __init btext_prepare_BAT(void)
 {
-       unsigned long vaddr = KERNELBASE + 0x10000000;
+       unsigned long vaddr = PAGE_OFFSET + 0x10000000;
        unsigned long addr;
        unsigned long lowbits;
 

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 7b93971..aacebb3 100644 (file)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -690,7 +690,7 @@ _GLOBAL(enter_rtas)
 
        /* Setup our real return addr */        
        SET_REG_TO_LABEL(r4,.rtas_return_loc)
-       SET_REG_TO_CONST(r9,KERNELBASE)
+       SET_REG_TO_CONST(r9,PAGE_OFFSET)
        sub     r4,r4,r9
                mtlr    r4
 
@@ -718,7 +718,7 @@ _GLOBAL(enter_rtas)
 _STATIC(rtas_return_loc)
        /* relocation is off at this point */
        mfspr   r4,SPRN_SPRG3           /* Get PACA */
-       SET_REG_TO_CONST(r5, KERNELBASE)
+       SET_REG_TO_CONST(r5, PAGE_OFFSET)
         sub     r4,r4,r5                /* RELOC the PACA base pointer */
 
        mfmsr   r6

diff --git a/arch/powerpc/kernel/lparmap.c b/arch/powerpc/kernel/lparmap.c
index 5a05a79..8a53d43 100644 (file)
--- a/arch/powerpc/kernel/lparmap.c
+++ b/arch/powerpc/kernel/lparmap.c
@@ -16,8 +16,8 @@ const struct LparMap __attribute__((__section__(".text"))) xLparMap = {
        .xSegmentTableOffs = STAB0_PAGE,
 
        .xEsids = {
-               { .xKernelEsid = GET_ESID(KERNELBASE),
-                 .xKernelVsid = KERNEL_VSID(KERNELBASE), },
+               { .xKernelEsid = GET_ESID(PAGE_OFFSET),
+                 .xKernelVsid = KERNEL_VSID(PAGE_OFFSET), },
                { .xKernelEsid = GET_ESID(VMALLOCBASE),
                  .xKernelVsid = KERNEL_VSID(VMALLOCBASE), },
        },
@@ -25,7 +25,7 @@ const struct LparMap __attribute__((__section__(".text"))) xLparMap = {
        .xRanges = {
                { .xPages = HvPagesToMap,
                  .xOffset = 0,
-                 .xVPN = KERNEL_VSID(KERNELBASE) << (SID_SHIFT - HW_PAGE_SHIFT),
+                 .xVPN = KERNEL_VSID(PAGE_OFFSET) << (SID_SHIFT - HW_PAGE_SHIFT),
                },
        },
 };

diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index ec0f06b..0b0fa47 100644 (file)
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -153,9 +153,8 @@ void kexec_copy_flush(struct kimage *image)
         * including ones that were in place on the original copy
         */
        for (i = 0; i < nr_segments; i++)
-               flush_icache_range(ranges[i].mem + KERNELBASE,
-                               ranges[i].mem + KERNELBASE +
-                               ranges[i].memsz);
+               flush_icache_range((unsigned long)__va(ranges[i].mem),
+                       (unsigned long)__va(ranges[i].mem + ranges[i].memsz));
 }
 
 #ifdef CONFIG_SMP

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 846a189..5bb433c 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -456,7 +456,7 @@ void __init htab_initialize(void)
 
        /* create bolted the linear mapping in the hash table */
        for (i=0; i < lmb.memory.cnt; i++) {
-               base = lmb.memory.region[i].base + KERNELBASE;
+               base = (unsigned long)__va(lmb.memory.region[i].base);
                size = lmb.memory.region[i].size;
 
                DBG("creating mapping for region: %lx : %lx\n", base, size);
@@ -498,8 +498,8 @@ void __init htab_initialize(void)
         * for either 4K or 16MB pages.
         */
        if (tce_alloc_start) {
-               tce_alloc_start += KERNELBASE;
-               tce_alloc_end += KERNELBASE;
+               tce_alloc_start = (unsigned long)__va(tce_alloc_start);
+               tce_alloc_end = (unsigned long)__va(tce_alloc_end);
 
                if (base + size >= tce_alloc_start)
                        tce_alloc_start = base + size + 1;

diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index a47b273..cc22570 100644 (file)
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -75,7 +75,7 @@ static void slb_flush_and_rebolt(void)
        vflags = SLB_VSID_KERNEL | virtual_llp;
 
        ksp_esid_data = mk_esid_data(get_paca()->kstack, 2);
-       if ((ksp_esid_data & ESID_MASK) == KERNELBASE)
+       if ((ksp_esid_data & ESID_MASK) == PAGE_OFFSET)
                ksp_esid_data &= ~SLB_ESID_V;
 
        /* We need to do this all in asm, so we're sure we don't touch
@@ -213,7 +213,7 @@ void slb_initialize(void)
        asm volatile("isync":::"memory");
        asm volatile("slbmte  %0,%0"::"r" (0) : "memory");
        asm volatile("isync; slbia; isync":::"memory");
-       create_slbe(KERNELBASE, lflags, 0);
+       create_slbe(PAGE_OFFSET, lflags, 0);
 
        /* VMALLOC space has 4K pages always for now */
        create_slbe(VMALLOCBASE, vflags, 1);

diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index 950ffc5..d1acee3 100644 (file)
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -37,9 +37,9 @@ _GLOBAL(slb_allocate_realmode)
 
        srdi    r9,r3,60                /* get region */
        srdi    r10,r3,28               /* get esid */
-       cmpldi  cr7,r9,0xc              /* cmp KERNELBASE for later use */
+       cmpldi  cr7,r9,0xc              /* cmp PAGE_OFFSET for later use */
 
-       /* r3 = address, r10 = esid, cr7 = <>KERNELBASE */
+       /* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */
        blt     cr7,0f                  /* user or kernel? */
 
        /* kernel address: proto-VSID = ESID */
@@ -166,7 +166,7 @@ _GLOBAL(slb_allocate_user)
 /*
  * Finish loading of an SLB entry and return
  *
- * r3 = EA, r10 = proto-VSID, r11 = flags, clobbers r9, cr7 = <>KERNELBASE
+ * r3 = EA, r10 = proto-VSID, r11 = flags, clobbers r9, cr7 = <> PAGE_OFFSET
  */
 slb_finish_load:
        ASM_VSID_SCRAMBLE(r10,r9)

diff --git a/arch/powerpc/mm/stab.c b/arch/powerpc/mm/stab.c
index a18dab0..82e4951 100644 (file)
--- a/arch/powerpc/mm/stab.c
+++ b/arch/powerpc/mm/stab.c
@@ -40,7 +40,7 @@ static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
        unsigned long entry, group, old_esid, castout_entry, i;
        unsigned int global_entry;
        struct stab_entry *ste, *castout_ste;
-       unsigned long kernel_segment = (esid << SID_SHIFT) >= KERNELBASE;
+       unsigned long kernel_segment = (esid << SID_SHIFT) >= PAGE_OFFSET;
 
        vsid_data = vsid << STE_VSID_SHIFT;
        esid_data = esid << SID_SHIFT | STE_ESID_KP | STE_ESID_V;
@@ -83,7 +83,7 @@ static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
                }
 
                /* Dont cast out the first kernel segment */
-               if ((castout_ste->esid_data & ESID_MASK) != KERNELBASE)
+               if ((castout_ste->esid_data & ESID_MASK) != PAGE_OFFSET)
                        break;
 
                castout_entry = (castout_entry + 1) & 0xf;
@@ -251,7 +251,7 @@ void stabs_alloc(void)
                        panic("Unable to allocate segment table for CPU %d.\n",
                              cpu);
 
-               newstab += KERNELBASE;
+               newstab = (unsigned long)__va(newstab);
 
                memset((void *)newstab, 0, HW_PAGE_SIZE);
 
@@ -270,11 +270,11 @@ void stabs_alloc(void)
  */
 void stab_initialize(unsigned long stab)
 {
-       unsigned long vsid = get_kernel_vsid(KERNELBASE);
+       unsigned long vsid = get_kernel_vsid(PAGE_OFFSET);
        unsigned long stabreal;
 
        asm volatile("isync; slbia; isync":::"memory");
-       make_ste(stab, GET_ESID(KERNELBASE), vsid);
+       make_ste(stab, GET_ESID(PAGE_OFFSET), vsid);
 
        /* Order update */
        asm volatile("sync":::"memory");

diff --git a/include/asm-powerpc/page.h b/include/asm-powerpc/page.h
index 94905ba..4696bdb 100644 (file)
--- a/include/asm-powerpc/page.h
+++ b/include/asm-powerpc/page.h
@@ -37,6 +37,20 @@
  */
 #define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))
 
+/*
+ * KERNELBASE is the virtual address of the start of the kernel, it's often
+ * the same as PAGE_OFFSET, but _might not be_.
+ *
+ * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
+ *
+ * To get a physical address from a virtual one you subtract PAGE_OFFSET,
+ * _not_ KERNELBASE.
+ *
+ * If you want to know something's offset from the start of the kernel you
+ * should subtract KERNELBASE.
+ *
+ * If you want to test if something's a kernel address, use is_kernel_addr().
+ */
 #define PAGE_OFFSET     ASM_CONST(CONFIG_KERNEL_START)
 #define KERNELBASE      PAGE_OFFSET
 
@@ -56,7 +70,7 @@
 #define pfn_to_kaddr(pfn)      __va((pfn) << PAGE_SHIFT)
 #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
-#define __va(x) ((void *)((unsigned long)(x) + KERNELBASE))
+#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
 
 /*