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6c284228eb
In the old days, _PAGE_EXEC didn't exist on 6xx aka book3s/32. Therefore, allthough __mapin_ram_chunk() was already mapping kernel text with PAGE_KERNEL_TEXT and the rest with PAGE_KERNEL, the entire memory was executable. Part of the memory (first 512kbytes) was mapped with BATs instead of page table, but it was also entirely mapped as executable. In commit385e89d5b2("powerpc/mm: add exec protection on powerpc 603"), we started adding exec protection to some 6xx, namely the 603, for pages mapped via pagetables. Then, in commit63b2bc6195("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX"), the exec protection was extended to BAT mapped memory, so that really only the kernel text could be executed. The problem here is that kexec is based on copying some code into upper part of memory then executing it from there in order to install a fresh new kernel at its definitive location. However, the code is position independant and first part of it is just there to deactivate the MMU and jump to the second part. So it is possible to run this first part inplace instead of running the copy. Once the MMU is off, there is no protection anymore and the second part of the code will just run as before. Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Fixes:63b2bc6195("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX") Cc: stable@vger.kernel.org # v5.1+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
156 lines
4.2 KiB
C
156 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_KEXEC_H
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#define _ASM_POWERPC_KEXEC_H
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#ifdef __KERNEL__
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#if defined(CONFIG_FSL_BOOKE) || defined(CONFIG_44x)
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/*
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* On FSL-BookE we setup a 1:1 mapping which covers the first 2GiB of memory
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* and therefore we can only deal with memory within this range
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*/
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#define KEXEC_SOURCE_MEMORY_LIMIT (2 * 1024 * 1024 * 1024UL - 1)
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#define KEXEC_DESTINATION_MEMORY_LIMIT (2 * 1024 * 1024 * 1024UL - 1)
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#define KEXEC_CONTROL_MEMORY_LIMIT (2 * 1024 * 1024 * 1024UL - 1)
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#else
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/*
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* Maximum page that is mapped directly into kernel memory.
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* XXX: Since we copy virt we can use any page we allocate
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*/
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#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
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/*
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* Maximum address we can reach in physical address mode.
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* XXX: I want to allow initrd in highmem. Otherwise set to rmo on LPAR.
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*/
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#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
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/* Maximum address we can use for the control code buffer */
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#ifdef __powerpc64__
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#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)
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#else
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/* TASK_SIZE, probably left over from use_mm ?? */
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#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
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#endif
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#endif
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#define KEXEC_CONTROL_PAGE_SIZE 4096
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/* The native architecture */
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#ifdef __powerpc64__
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#define KEXEC_ARCH KEXEC_ARCH_PPC64
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#else
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#define KEXEC_ARCH KEXEC_ARCH_PPC
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#endif
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#define KEXEC_STATE_NONE 0
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#define KEXEC_STATE_IRQS_OFF 1
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#define KEXEC_STATE_REAL_MODE 2
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#ifndef __ASSEMBLY__
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#include <asm/reg.h>
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typedef void (*crash_shutdown_t)(void);
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#ifdef CONFIG_KEXEC_CORE
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/*
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* This function is responsible for capturing register states if coming
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* via panic or invoking dump using sysrq-trigger.
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*/
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static inline void crash_setup_regs(struct pt_regs *newregs,
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struct pt_regs *oldregs)
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{
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if (oldregs)
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memcpy(newregs, oldregs, sizeof(*newregs));
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else
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ppc_save_regs(newregs);
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}
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extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
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master to copy new code to 0 */
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extern int crashing_cpu;
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extern void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *));
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extern void crash_ipi_callback(struct pt_regs *);
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extern int crash_wake_offline;
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struct kimage;
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struct pt_regs;
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extern void default_machine_kexec(struct kimage *image);
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extern int default_machine_kexec_prepare(struct kimage *image);
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extern void default_machine_crash_shutdown(struct pt_regs *regs);
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extern int crash_shutdown_register(crash_shutdown_t handler);
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extern int crash_shutdown_unregister(crash_shutdown_t handler);
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extern void crash_kexec_secondary(struct pt_regs *regs);
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extern int overlaps_crashkernel(unsigned long start, unsigned long size);
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extern void reserve_crashkernel(void);
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extern void machine_kexec_mask_interrupts(void);
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static inline bool kdump_in_progress(void)
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{
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return crashing_cpu >= 0;
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}
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void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_code_buffer,
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unsigned long start_address) __noreturn;
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#ifdef CONFIG_KEXEC_FILE
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extern const struct kexec_file_ops kexec_elf64_ops;
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#ifdef CONFIG_IMA_KEXEC
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#define ARCH_HAS_KIMAGE_ARCH
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struct kimage_arch {
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phys_addr_t ima_buffer_addr;
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size_t ima_buffer_size;
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};
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#endif
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int setup_purgatory(struct kimage *image, const void *slave_code,
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const void *fdt, unsigned long kernel_load_addr,
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unsigned long fdt_load_addr);
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int setup_new_fdt(const struct kimage *image, void *fdt,
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unsigned long initrd_load_addr, unsigned long initrd_len,
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const char *cmdline);
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int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
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#endif /* CONFIG_KEXEC_FILE */
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#else /* !CONFIG_KEXEC_CORE */
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static inline void crash_kexec_secondary(struct pt_regs *regs) { }
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static inline int overlaps_crashkernel(unsigned long start, unsigned long size)
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{
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return 0;
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}
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static inline void reserve_crashkernel(void) { ; }
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static inline int crash_shutdown_register(crash_shutdown_t handler)
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{
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return 0;
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}
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static inline int crash_shutdown_unregister(crash_shutdown_t handler)
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{
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return 0;
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}
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static inline bool kdump_in_progress(void)
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{
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return false;
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}
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static inline void crash_ipi_callback(struct pt_regs *regs) { }
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static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
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{
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}
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#endif /* CONFIG_KEXEC_CORE */
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#endif /* ! __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_KEXEC_H */
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