powerpc/8xx: Map 32Mb of RAM at init.

At the time being, initial MMU setup allows 24 Mbytes
of DATA and 8 Mbytes of code.

Some debug setup like CONFIG_KASAN generate huge
kernels with text size over the 8M limit and data over the
24 Mbytes limit.

Here is an 8xx kernel compiled with CONFIG_KASAN_INLINE for
one of my boards:

[root@po16846vm linux-powerpc]# size -x vmlinux
   text	   data	    bss	    dec	    hex	filename
0x111019c	0x41b0d4	0x490de0	26984528	19bc050	vmlinux

This patch maps up to 32 Mbytes code based on _einittext symbol
and allows 32 Mbytes of memory instead of 24.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 7e14796..52c9291 100644 (file)
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -337,8 +337,8 @@ InstructionTLBMiss:
        rlwinm  r10, r10, 16, 0xfff8
        cmpli   cr0, r10, PAGE_OFFSET@h
 #ifndef CONFIG_PIN_TLB_TEXT
-       /* It is assumed that kernel code fits into the first 8M page */
-0:     cmpli   cr7, r10, (PAGE_OFFSET + 0x0800000)@h
+       /* It is assumed that kernel code fits into the first 32M */
+0:     cmpli   cr7, r10, (PAGE_OFFSET + 0x2000000)@h
        patch_site      0b, patch__itlbmiss_linmem_top
 #endif
 #endif
@@ -434,7 +434,7 @@ DataStoreTLBMiss:
 #ifndef CONFIG_PIN_TLB_IMMR
        cmpli   cr6, r10, VIRT_IMMR_BASE@h
 #endif
-0:     cmpli   cr7, r10, (PAGE_OFFSET + 0x1800000)@h
+0:     cmpli   cr7, r10, (PAGE_OFFSET + 0x2000000)@h
        patch_site      0b, patch__dtlbmiss_linmem_top
 
        mfspr   r10, SPRN_M_TWB /* Get level 1 table */
@@ -886,28 +886,11 @@ initial_mmu:
        mtspr   SPRN_MD_CTR, r10        /* remove PINNED DTLB entries */
 
        tlbia                   /* Invalidate all TLB entries */
-#ifdef CONFIG_PIN_TLB_TEXT
-       lis     r8, MI_RSV4I@h
-       ori     r8, r8, 0x1c00
-
-       mtspr   SPRN_MI_CTR, r8 /* Set instruction MMU control */
-#endif
-
 #ifdef CONFIG_PIN_TLB_DATA
        oris    r10, r10, MD_RSV4I@h
        mtspr   SPRN_MD_CTR, r10        /* Set data TLB control */
 #endif
 
-       /* Now map the lower 8 Meg into the ITLB. */
-       lis     r8, KERNELBASE@h        /* Create vaddr for TLB */
-       ori     r8, r8, MI_EVALID       /* Mark it valid */
-       mtspr   SPRN_MI_EPN, r8
-       li      r8, MI_PS8MEG /* Set 8M byte page */
-       ori     r8, r8, MI_SVALID       /* Make it valid */
-       mtspr   SPRN_MI_TWC, r8
-       li      r8, MI_BOOTINIT         /* Create RPN for address 0 */
-       mtspr   SPRN_MI_RPN, r8         /* Store TLB entry */
-
        lis     r8, MI_APG_INIT@h       /* Set protection modes */
        ori     r8, r8, MI_APG_INIT@l
        mtspr   SPRN_MI_AP, r8
@@ -937,6 +920,34 @@ initial_mmu:
        mtspr   SPRN_MD_RPN, r8
 #endif
 
+       /* Now map the lower RAM (up to 32 Mbytes) into the ITLB. */
+#ifdef CONFIG_PIN_TLB_TEXT
+       lis     r8, MI_RSV4I@h
+       ori     r8, r8, 0x1c00
+#endif
+       li      r9, 4                           /* up to 4 pages of 8M */
+       mtctr   r9
+       lis     r9, KERNELBASE@h                /* Create vaddr for TLB */
+       li      r10, MI_PS8MEG | MI_SVALID      /* Set 8M byte page */
+       li      r11, MI_BOOTINIT                /* Create RPN for address 0 */
+       lis     r12, _einittext@h
+       ori     r12, r12, _einittext@l
+1:
+#ifdef CONFIG_PIN_TLB_TEXT
+       mtspr   SPRN_MI_CTR, r8 /* Set instruction MMU control */
+       addi    r8, r8, 0x100
+#endif
+
+       ori     r0, r9, MI_EVALID               /* Mark it valid */
+       mtspr   SPRN_MI_EPN, r0
+       mtspr   SPRN_MI_TWC, r10
+       mtspr   SPRN_MI_RPN, r11                /* Store TLB entry */
+       addis   r9, r9, 0x80
+       addis   r11, r11, 0x80
+
+       cmpl    cr0, r9, r12
+       bdnzf   gt, 1b
+
        /* Since the cache is enabled according to the information we
         * just loaded into the TLB, invalidate and enable the caches here.
         * We should probably check/set other modes....later.

diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index 174452f..e95196f 100644 (file)
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c
@@ -112,6 +112,9 @@ unsigned long __init mmu_mapin_ram(unsigned long top)
                        mmu_patch_cmp_limit(&patch__itlbmiss_linmem_top, 0);
        } else {
                mapped = top & ~(LARGE_PAGE_SIZE_8M - 1);
+               if (!IS_ENABLED(CONFIG_PIN_TLB_TEXT))
+                       mmu_patch_cmp_limit(&patch__itlbmiss_linmem_top,
+                                           _ALIGN(__pa(_einittext), 8 << 20));
        }
 
        mmu_patch_cmp_limit(&patch__dtlbmiss_linmem_top, mapped);
@@ -140,8 +143,8 @@ void __init setup_initial_memory_limit(phys_addr_t first_memblock_base,
         */
        BUG_ON(first_memblock_base != 0);
 
-       /* 8xx can only access 24MB at the moment */
-       memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01800000));
+       /* 8xx can only access 32MB at the moment */
+       memblock_set_current_limit(min_t(u64, first_memblock_size, 0x02000000));
 }
 
 /*