From 2b0e86cc5de6dabadc2d64cefa429fc227c8a756 Mon Sep 17 00:00:00 2001 From: Jason Yan Date: Fri, 20 Sep 2019 17:45:40 +0800 Subject: powerpc/fsl_booke/32: implement KASLR infrastructure This patch add support to boot kernel from places other than KERNELBASE. Since CONFIG_RELOCATABLE has already supported, what we need to do is map or copy kernel to a proper place and relocate. Freescale Book-E parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1 entries are not suitable to map the kernel directly in a randomized region, so we chose to copy the kernel to a proper place and restart to relocate. The offset of the kernel was not randomized yet(a fixed 64M is set). We will randomize it in the next patch. Signed-off-by: Jason Yan Tested-by: Diana Craciun Reviewed-by: Christophe Leroy Signed-off-by: Scott Wood [mpe: Use PTRRELOC() in early_init()] Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/early_32.c | 9 ++++++--- arch/powerpc/kernel/fsl_booke_entry_mapping.S | 15 +++++++-------- arch/powerpc/kernel/head_fsl_booke.S | 13 ++++++++++--- 3 files changed, 23 insertions(+), 14 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/early_32.c b/arch/powerpc/kernel/early_32.c index 3482118ffe76..ef2ad4945904 100644 --- a/arch/powerpc/kernel/early_32.c +++ b/arch/powerpc/kernel/early_32.c @@ -19,10 +19,13 @@ */ notrace unsigned long __init early_init(unsigned long dt_ptr) { - unsigned long offset = reloc_offset(); + unsigned long kva, offset = reloc_offset(); + + kva = *PTRRELOC(&kernstart_virt_addr); /* First zero the BSS */ - memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start); + if (kva == KERNELBASE) + memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start); /* * Identify the CPU type and fix up code sections @@ -32,5 +35,5 @@ notrace unsigned long __init early_init(unsigned long dt_ptr) apply_feature_fixups(); - return KERNELBASE + offset; + return kva + offset; } diff --git a/arch/powerpc/kernel/fsl_booke_entry_mapping.S b/arch/powerpc/kernel/fsl_booke_entry_mapping.S index f4d3eaae54a9..8bccce6544b5 100644 --- a/arch/powerpc/kernel/fsl_booke_entry_mapping.S +++ b/arch/powerpc/kernel/fsl_booke_entry_mapping.S @@ -155,23 +155,22 @@ skpinv: addi r6,r6,1 /* Increment */ #if defined(ENTRY_MAPPING_BOOT_SETUP) -/* 6. Setup KERNELBASE mapping in TLB1[0] */ +/* 6. Setup kernstart_virt_addr mapping in TLB1[0] */ lis r6,0x1000 /* Set MAS0(TLBSEL) = TLB1(1), ESEL = 0 */ mtspr SPRN_MAS0,r6 lis r6,(MAS1_VALID|MAS1_IPROT)@h ori r6,r6,(MAS1_TSIZE(BOOK3E_PAGESZ_64M))@l mtspr SPRN_MAS1,r6 - lis r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, MAS2_M_IF_NEEDED)@h - ori r6,r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, MAS2_M_IF_NEEDED)@l + lis r6,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@h + ori r6,r6,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@l + and r6,r6,r20 + ori r6,r6,MAS2_M_IF_NEEDED@l mtspr SPRN_MAS2,r6 mtspr SPRN_MAS3,r8 tlbwe -/* 7. Jump to KERNELBASE mapping */ - lis r6,(KERNELBASE & ~0xfff)@h - ori r6,r6,(KERNELBASE & ~0xfff)@l - rlwinm r7,r25,0,0x03ffffff - add r6,r7,r6 +/* 7. Jump to kernstart_virt_addr mapping */ + mr r6,r20 #elif defined(ENTRY_MAPPING_KEXEC_SETUP) /* diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S index d9f599b01ff1..838d9d4650c7 100644 --- a/arch/powerpc/kernel/head_fsl_booke.S +++ b/arch/powerpc/kernel/head_fsl_booke.S @@ -155,6 +155,8 @@ _ENTRY(_start); */ _ENTRY(__early_start) + LOAD_REG_ADDR_PIC(r20, kernstart_virt_addr) + lwz r20,0(r20) #define ENTRY_MAPPING_BOOT_SETUP #include "fsl_booke_entry_mapping.S" @@ -277,8 +279,8 @@ set_ivor: ori r6, r6, swapper_pg_dir@l lis r5, abatron_pteptrs@h ori r5, r5, abatron_pteptrs@l - lis r4, KERNELBASE@h - ori r4, r4, KERNELBASE@l + lis r3, kernstart_virt_addr@ha + lwz r4, kernstart_virt_addr@l(r3) stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ stw r6, 0(r5) @@ -1067,7 +1069,12 @@ __secondary_start: mr r5,r25 /* phys kernel start */ rlwinm r5,r5,0,~0x3ffffff /* aligned 64M */ subf r4,r5,r4 /* memstart_addr - phys kernel start */ - li r5,0 /* no device tree */ + lis r7,KERNELBASE@h + ori r7,r7,KERNELBASE@l + cmpw r20,r7 /* if kernstart_virt_addr != KERNELBASE, randomized */ + beq 2f + li r4,0 +2: li r5,0 /* no device tree */ li r6,0 /* not boot cpu */ bl restore_to_as0 -- cgit v1.2.3