| Message ID | 20190730074225.39544-7-yanaijie@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | implement KASLR for powerpc/fsl_booke/32 | expand |
Le 30/07/2019 à 09:42, Jason Yan a écrit : > 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 <yanaijie@huawei.com> > Cc: Diana Craciun <diana.craciun@nxp.com> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Christophe Leroy <christophe.leroy@c-s.fr> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Kees Cook <keescook@chromium.org> > --- > arch/powerpc/Kconfig | 11 +++ > arch/powerpc/kernel/Makefile | 1 + > arch/powerpc/kernel/early_32.c | 2 +- > arch/powerpc/kernel/fsl_booke_entry_mapping.S | 13 ++- > arch/powerpc/kernel/head_fsl_booke.S | 15 +++- > arch/powerpc/kernel/kaslr_booke.c | 84 +++++++++++++++++++ > arch/powerpc/mm/mmu_decl.h | 6 ++ > arch/powerpc/mm/nohash/fsl_booke.c | 7 +- > 8 files changed, 126 insertions(+), 13 deletions(-) > create mode 100644 arch/powerpc/kernel/kaslr_booke.c > [...] > diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S > index 2083382dd662..a466c0f0d028 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, kimage_vaddr) > + 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, kimage_vaddr@ha > + lwz r4, kimage_vaddr@l(r3) > stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ > stw r6, 0(r5) > > @@ -1067,7 +1069,14 @@ __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 */ > +#ifdef CONFIG_RANDOMIZE_BASE Is that #ifdef really necessary ? Wouldn't it also work as expected when CONFIG_RANDOMIZE_BASE is not selected ? > + lis r7,KERNELBASE@h > + ori r7,r7,KERNELBASE@l > + cmpw r20,r7 /* if kimage_vaddr != KERNELBASE, randomized */ > + beq 2f > + li r4,0 > +#endif > +2: li r5,0 /* no device tree */ > li r6,0 /* not boot cpu */ > bl restore_to_as0 > > diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c > new file mode 100644 > index 000000000000..960bce4aa8b9 > --- /dev/null > +++ b/arch/powerpc/kernel/kaslr_booke.c > @@ -0,0 +1,84 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2019 Jason Yan <yanaijie@huawei.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include <linux/signal.h> > +#include <linux/sched.h> > +#include <linux/kernel.h> > +#include <linux/errno.h> > +#include <linux/string.h> > +#include <linux/types.h> > +#include <linux/ptrace.h> > +#include <linux/mman.h> > +#include <linux/mm.h> > +#include <linux/swap.h> > +#include <linux/stddef.h> > +#include <linux/vmalloc.h> > +#include <linux/init.h> > +#include <linux/delay.h> > +#include <linux/highmem.h> > +#include <linux/memblock.h> > +#include <asm/pgalloc.h> > +#include <asm/prom.h> > +#include <asm/io.h> > +#include <asm/mmu_context.h> > +#include <asm/pgtable.h> > +#include <asm/mmu.h> > +#include <linux/uaccess.h> > +#include <asm/smp.h> > +#include <asm/machdep.h> > +#include <asm/setup.h> > +#include <asm/paca.h> > +#include <mm/mmu_decl.h> > + > +extern int is_second_reloc; Couldn't the above be a bool ? > + > +static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size, > + unsigned long kernel_sz) > +{ > + /* return a fixed offset of 64M for now */ > + return 0x4000000; 64 << 20 would maybe be more explicit than 0x4000000. Or return SZ_64M ? Christophe > +} > + > +/* > + * To see if we need to relocate the kernel to a random offset > + * void *dt_ptr - address of the device tree > + * phys_addr_t size - size of the first memory block > + */ > +notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size) > +{ > + unsigned long tlb_virt; > + phys_addr_t tlb_phys; > + unsigned long offset; > + unsigned long kernel_sz; > + > + kernel_sz = (unsigned long)_end - KERNELBASE; > + > + offset = kaslr_choose_location(dt_ptr, size, kernel_sz); > + > + if (offset == 0) > + return; > + > + kimage_vaddr += offset; > + kernstart_addr += offset; > + > + is_second_reloc = 1; > + > + if (offset >= SZ_64M) { > + tlb_virt = round_down(kimage_vaddr, SZ_64M); > + tlb_phys = round_down(kernstart_addr, SZ_64M); > + > + /* Create kernel map to relocate in */ > + create_tlb_entry(tlb_phys, tlb_virt, 1); > + } > + > + /* Copy the kernel to it's new location and run */ > + memcpy((void *)kimage_vaddr, (void *)KERNELBASE, kernel_sz); > + > + reloc_kernel_entry(dt_ptr, kimage_vaddr); > +} > diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h > index 804da298beb3..9332772c8a66 100644 > --- a/arch/powerpc/mm/mmu_decl.h > +++ b/arch/powerpc/mm/mmu_decl.h > @@ -148,6 +148,12 @@ void reloc_kernel_entry(void *fdt, int addr); > extern void loadcam_entry(unsigned int index); > extern void loadcam_multi(int first_idx, int num, int tmp_idx); > > +#ifdef CONFIG_RANDOMIZE_BASE > +void kaslr_early_init(void *dt_ptr, phys_addr_t size); > +#else > +static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {} > +#endif > + > struct tlbcam { > u32 MAS0; > u32 MAS1; > diff --git a/arch/powerpc/mm/nohash/fsl_booke.c b/arch/powerpc/mm/nohash/fsl_booke.c > index 556e3cd52a35..8d25a8dc965f 100644 > --- a/arch/powerpc/mm/nohash/fsl_booke.c > +++ b/arch/powerpc/mm/nohash/fsl_booke.c > @@ -263,7 +263,8 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base, > int __initdata is_second_reloc; > notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) > { > - unsigned long base = KERNELBASE; > + unsigned long base = kimage_vaddr; > + phys_addr_t size; > > kernstart_addr = start; > if (is_second_reloc) { > @@ -291,7 +292,7 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) > start &= ~0x3ffffff; > base &= ~0x3ffffff; > virt_phys_offset = base - start; > - early_get_first_memblock_info(__va(dt_ptr), NULL); > + early_get_first_memblock_info(__va(dt_ptr), &size); > /* > * We now get the memstart_addr, then we should check if this > * address is the same as what the PAGE_OFFSET map to now. If > @@ -316,6 +317,8 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) > /* We should never reach here */ > panic("Relocation error"); > } > + > + kaslr_early_init(__va(dt_ptr), size); > } > #endif > #endif >
On 2019/7/30 17:34, Christophe Leroy wrote: > > > Le 30/07/2019 à 09:42, Jason Yan a écrit : >> 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 <yanaijie@huawei.com> >> Cc: Diana Craciun <diana.craciun@nxp.com> >> Cc: Michael Ellerman <mpe@ellerman.id.au> >> Cc: Christophe Leroy <christophe.leroy@c-s.fr> >> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> >> Cc: Paul Mackerras <paulus@samba.org> >> Cc: Nicholas Piggin <npiggin@gmail.com> >> Cc: Kees Cook <keescook@chromium.org> >> --- >> arch/powerpc/Kconfig | 11 +++ >> arch/powerpc/kernel/Makefile | 1 + >> arch/powerpc/kernel/early_32.c | 2 +- >> arch/powerpc/kernel/fsl_booke_entry_mapping.S | 13 ++- >> arch/powerpc/kernel/head_fsl_booke.S | 15 +++- >> arch/powerpc/kernel/kaslr_booke.c | 84 +++++++++++++++++++ >> arch/powerpc/mm/mmu_decl.h | 6 ++ >> arch/powerpc/mm/nohash/fsl_booke.c | 7 +- >> 8 files changed, 126 insertions(+), 13 deletions(-) >> create mode 100644 arch/powerpc/kernel/kaslr_booke.c >> > > [...] > >> diff --git a/arch/powerpc/kernel/head_fsl_booke.S >> b/arch/powerpc/kernel/head_fsl_booke.S >> index 2083382dd662..a466c0f0d028 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, kimage_vaddr) >> + 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, kimage_vaddr@ha >> + lwz r4, kimage_vaddr@l(r3) >> stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ >> stw r6, 0(r5) >> @@ -1067,7 +1069,14 @@ __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 */ >> +#ifdef CONFIG_RANDOMIZE_BASE > > Is that #ifdef really necessary ? Wouldn't it also work as expected when > CONFIG_RANDOMIZE_BASE is not selected ? > Yes, it will also work if CONFIG_RANDOMIZE_BASE is not enabled. I can remove it. >> + lis r7,KERNELBASE@h >> + ori r7,r7,KERNELBASE@l >> + cmpw r20,r7 /* if kimage_vaddr != KERNELBASE, >> randomized */ >> + beq 2f >> + li r4,0 >> +#endif >> +2: li r5,0 /* no device tree */ >> li r6,0 /* not boot cpu */ >> bl restore_to_as0 >> diff --git a/arch/powerpc/kernel/kaslr_booke.c >> b/arch/powerpc/kernel/kaslr_booke.c >> new file mode 100644 >> index 000000000000..960bce4aa8b9 >> --- /dev/null >> +++ b/arch/powerpc/kernel/kaslr_booke.c >> @@ -0,0 +1,84 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (C) 2019 Jason Yan <yanaijie@huawei.com> >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + */ >> + >> +#include <linux/signal.h> >> +#include <linux/sched.h> >> +#include <linux/kernel.h> >> +#include <linux/errno.h> >> +#include <linux/string.h> >> +#include <linux/types.h> >> +#include <linux/ptrace.h> >> +#include <linux/mman.h> >> +#include <linux/mm.h> >> +#include <linux/swap.h> >> +#include <linux/stddef.h> >> +#include <linux/vmalloc.h> >> +#include <linux/init.h> >> +#include <linux/delay.h> >> +#include <linux/highmem.h> >> +#include <linux/memblock.h> >> +#include <asm/pgalloc.h> >> +#include <asm/prom.h> >> +#include <asm/io.h> >> +#include <asm/mmu_context.h> >> +#include <asm/pgtable.h> >> +#include <asm/mmu.h> >> +#include <linux/uaccess.h> >> +#include <asm/smp.h> >> +#include <asm/machdep.h> >> +#include <asm/setup.h> >> +#include <asm/paca.h> >> +#include <mm/mmu_decl.h> >> + >> +extern int is_second_reloc; > > Couldn't the above be a bool ? > This variable is both used in C and assembly. Use int make it more explicit to compare it with 0 or 1 in assembly. >> + >> +static unsigned long __init kaslr_choose_location(void *dt_ptr, >> phys_addr_t size, >> + unsigned long kernel_sz) >> +{ >> + /* return a fixed offset of 64M for now */ >> + return 0x4000000; > > 64 << 20 would maybe be more explicit than 0x4000000. > > Or return SZ_64M ? > SZ_64M would be good. > Christophe > >> +} >> + >> +/* >> + * To see if we need to relocate the kernel to a random offset >> + * void *dt_ptr - address of the device tree >> + * phys_addr_t size - size of the first memory block >> + */ >> +notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size) >> +{ >> + unsigned long tlb_virt; >> + phys_addr_t tlb_phys; >> + unsigned long offset; >> + unsigned long kernel_sz; >> + >> + kernel_sz = (unsigned long)_end - KERNELBASE; >> + >> + offset = kaslr_choose_location(dt_ptr, size, kernel_sz); >> + >> + if (offset == 0) >> + return; >> + >> + kimage_vaddr += offset; >> + kernstart_addr += offset; >> + >> + is_second_reloc = 1; >> + >> + if (offset >= SZ_64M) { >> + tlb_virt = round_down(kimage_vaddr, SZ_64M); >> + tlb_phys = round_down(kernstart_addr, SZ_64M); >> + >> + /* Create kernel map to relocate in */ >> + create_tlb_entry(tlb_phys, tlb_virt, 1); >> + } >> + >> + /* Copy the kernel to it's new location and run */ >> + memcpy((void *)kimage_vaddr, (void *)KERNELBASE, kernel_sz); >> + >> + reloc_kernel_entry(dt_ptr, kimage_vaddr); >> +} >> diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h >> index 804da298beb3..9332772c8a66 100644 >> --- a/arch/powerpc/mm/mmu_decl.h >> +++ b/arch/powerpc/mm/mmu_decl.h >> @@ -148,6 +148,12 @@ void reloc_kernel_entry(void *fdt, int addr); >> extern void loadcam_entry(unsigned int index); >> extern void loadcam_multi(int first_idx, int num, int tmp_idx); >> +#ifdef CONFIG_RANDOMIZE_BASE >> +void kaslr_early_init(void *dt_ptr, phys_addr_t size); >> +#else >> +static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {} >> +#endif >> + >> struct tlbcam { >> u32 MAS0; >> u32 MAS1; >> diff --git a/arch/powerpc/mm/nohash/fsl_booke.c >> b/arch/powerpc/mm/nohash/fsl_booke.c >> index 556e3cd52a35..8d25a8dc965f 100644 >> --- a/arch/powerpc/mm/nohash/fsl_booke.c >> +++ b/arch/powerpc/mm/nohash/fsl_booke.c >> @@ -263,7 +263,8 @@ void setup_initial_memory_limit(phys_addr_t >> first_memblock_base, >> int __initdata is_second_reloc; >> notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) >> { >> - unsigned long base = KERNELBASE; >> + unsigned long base = kimage_vaddr; >> + phys_addr_t size; >> kernstart_addr = start; >> if (is_second_reloc) { >> @@ -291,7 +292,7 @@ notrace void __init relocate_init(u64 dt_ptr, >> phys_addr_t start) >> start &= ~0x3ffffff; >> base &= ~0x3ffffff; >> virt_phys_offset = base - start; >> - early_get_first_memblock_info(__va(dt_ptr), NULL); >> + early_get_first_memblock_info(__va(dt_ptr), &size); >> /* >> * We now get the memstart_addr, then we should check if this >> * address is the same as what the PAGE_OFFSET map to now. If >> @@ -316,6 +317,8 @@ notrace void __init relocate_init(u64 dt_ptr, >> phys_addr_t start) >> /* We should never reach here */ >> panic("Relocation error"); >> } >> + >> + kaslr_early_init(__va(dt_ptr), size); >> } >> #endif >> #endif >> > > . >
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 77f6ebf97113..755378887912 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -548,6 +548,17 @@ config RELOCATABLE setting can still be useful to bootwrappers that need to know the load address of the kernel (eg. u-boot/mkimage). +config RANDOMIZE_BASE + bool "Randomize the address of the kernel image" + depends on (FSL_BOOKE && FLATMEM && PPC32) + select RELOCATABLE + help + Randomizes the virtual address at which the kernel image is + loaded, as a security feature that deters exploit attempts + relying on knowledge of the location of kernel internals. + + If unsure, say N. + config RELOCATABLE_TEST bool "Test relocatable kernel" depends on (PPC64 && RELOCATABLE) diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index ea0c69236789..32f6c5b99307 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -106,6 +106,7 @@ extra-$(CONFIG_PPC_8xx) := head_8xx.o extra-y += vmlinux.lds obj-$(CONFIG_RELOCATABLE) += reloc_$(BITS).o +obj-$(CONFIG_RANDOMIZE_BASE) += kaslr_booke.o obj-$(CONFIG_PPC32) += entry_32.o setup_32.o early_32.o obj-$(CONFIG_PPC64) += dma-iommu.o iommu.o diff --git a/arch/powerpc/kernel/early_32.c b/arch/powerpc/kernel/early_32.c index 3482118ffe76..fe8347cdc07d 100644 --- a/arch/powerpc/kernel/early_32.c +++ b/arch/powerpc/kernel/early_32.c @@ -32,5 +32,5 @@ notrace unsigned long __init early_init(unsigned long dt_ptr) apply_feature_fixups(); - return KERNELBASE + offset; + return kimage_vaddr + offset; } diff --git a/arch/powerpc/kernel/fsl_booke_entry_mapping.S b/arch/powerpc/kernel/fsl_booke_entry_mapping.S index de0980945510..6d2967673ac7 100644 --- a/arch/powerpc/kernel/fsl_booke_entry_mapping.S +++ b/arch/powerpc/kernel/fsl_booke_entry_mapping.S @@ -161,17 +161,16 @@ skpinv: addi r6,r6,1 /* Increment */ 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, M_IF_NEEDED)@h - ori r6,r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_NEEDED)@l - mtspr SPRN_MAS2,r6 + 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,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 + 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 2083382dd662..a466c0f0d028 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, kimage_vaddr) + 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, kimage_vaddr@ha + lwz r4, kimage_vaddr@l(r3) stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ stw r6, 0(r5) @@ -1067,7 +1069,14 @@ __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 */ +#ifdef CONFIG_RANDOMIZE_BASE + lis r7,KERNELBASE@h + ori r7,r7,KERNELBASE@l + cmpw r20,r7 /* if kimage_vaddr != KERNELBASE, randomized */ + beq 2f + li r4,0 +#endif +2: li r5,0 /* no device tree */ li r6,0 /* not boot cpu */ bl restore_to_as0 diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c new file mode 100644 index 000000000000..960bce4aa8b9 --- /dev/null +++ b/arch/powerpc/kernel/kaslr_booke.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2019 Jason Yan <yanaijie@huawei.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/ptrace.h> +#include <linux/mman.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/stddef.h> +#include <linux/vmalloc.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/highmem.h> +#include <linux/memblock.h> +#include <asm/pgalloc.h> +#include <asm/prom.h> +#include <asm/io.h> +#include <asm/mmu_context.h> +#include <asm/pgtable.h> +#include <asm/mmu.h> +#include <linux/uaccess.h> +#include <asm/smp.h> +#include <asm/machdep.h> +#include <asm/setup.h> +#include <asm/paca.h> +#include <mm/mmu_decl.h> + +extern int is_second_reloc; + +static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size, + unsigned long kernel_sz) +{ + /* return a fixed offset of 64M for now */ + return 0x4000000; +} + +/* + * To see if we need to relocate the kernel to a random offset + * void *dt_ptr - address of the device tree + * phys_addr_t size - size of the first memory block + */ +notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size) +{ + unsigned long tlb_virt; + phys_addr_t tlb_phys; + unsigned long offset; + unsigned long kernel_sz; + + kernel_sz = (unsigned long)_end - KERNELBASE; + + offset = kaslr_choose_location(dt_ptr, size, kernel_sz); + + if (offset == 0) + return; + + kimage_vaddr += offset; + kernstart_addr += offset; + + is_second_reloc = 1; + + if (offset >= SZ_64M) { + tlb_virt = round_down(kimage_vaddr, SZ_64M); + tlb_phys = round_down(kernstart_addr, SZ_64M); + + /* Create kernel map to relocate in */ + create_tlb_entry(tlb_phys, tlb_virt, 1); + } + + /* Copy the kernel to it's new location and run */ + memcpy((void *)kimage_vaddr, (void *)KERNELBASE, kernel_sz); + + reloc_kernel_entry(dt_ptr, kimage_vaddr); +} diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h index 804da298beb3..9332772c8a66 100644 --- a/arch/powerpc/mm/mmu_decl.h +++ b/arch/powerpc/mm/mmu_decl.h @@ -148,6 +148,12 @@ void reloc_kernel_entry(void *fdt, int addr); extern void loadcam_entry(unsigned int index); extern void loadcam_multi(int first_idx, int num, int tmp_idx); +#ifdef CONFIG_RANDOMIZE_BASE +void kaslr_early_init(void *dt_ptr, phys_addr_t size); +#else +static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {} +#endif + struct tlbcam { u32 MAS0; u32 MAS1; diff --git a/arch/powerpc/mm/nohash/fsl_booke.c b/arch/powerpc/mm/nohash/fsl_booke.c index 556e3cd52a35..8d25a8dc965f 100644 --- a/arch/powerpc/mm/nohash/fsl_booke.c +++ b/arch/powerpc/mm/nohash/fsl_booke.c @@ -263,7 +263,8 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base, int __initdata is_second_reloc; notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) { - unsigned long base = KERNELBASE; + unsigned long base = kimage_vaddr; + phys_addr_t size; kernstart_addr = start; if (is_second_reloc) { @@ -291,7 +292,7 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) start &= ~0x3ffffff; base &= ~0x3ffffff; virt_phys_offset = base - start; - early_get_first_memblock_info(__va(dt_ptr), NULL); + early_get_first_memblock_info(__va(dt_ptr), &size); /* * We now get the memstart_addr, then we should check if this * address is the same as what the PAGE_OFFSET map to now. If @@ -316,6 +317,8 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start) /* We should never reach here */ panic("Relocation error"); } + + kaslr_early_init(__va(dt_ptr), size); } #endif #endif
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 <yanaijie@huawei.com> Cc: Diana Craciun <diana.craciun@nxp.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Kees Cook <keescook@chromium.org> --- arch/powerpc/Kconfig | 11 +++ arch/powerpc/kernel/Makefile | 1 + arch/powerpc/kernel/early_32.c | 2 +- arch/powerpc/kernel/fsl_booke_entry_mapping.S | 13 ++- arch/powerpc/kernel/head_fsl_booke.S | 15 +++- arch/powerpc/kernel/kaslr_booke.c | 84 +++++++++++++++++++ arch/powerpc/mm/mmu_decl.h | 6 ++ arch/powerpc/mm/nohash/fsl_booke.c | 7 +- 8 files changed, 126 insertions(+), 13 deletions(-) create mode 100644 arch/powerpc/kernel/kaslr_booke.c