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@xxxxxxxxxx> Cc: Diana Craciun <diana.craciun@xxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> --- 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.Sindex 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_BASEIs 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_as0diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.cnew 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@xxxxxxxxxx> + * + * 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.cindex 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.
