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RISC-V Fixes for 6.10-rc3

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* Another fix to avoid allocating pages that overlap with ERR_PTR, which
   manifests on rv32.
 * A revert for the badaccess patch I incorrectly picked up an early
   version of.
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Merge tag 'riscv-for-linus-6.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - Another fix to avoid allocating pages that overlap with ERR_PTR,
   which manifests on rv32

 - A revert for the badaccess patch I incorrectly picked up an early
   version of

* tag 'riscv-for-linus-6.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  Revert "riscv: mm: accelerate pagefault when badaccess"
  riscv: fix overlap of allocated page and PTR_ERR
This commit is contained in:
Linus Torvalds 2024-06-07 14:47:38 -07:00
commit 0a02756d91
2 changed files with 13 additions and 12 deletions
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4
arch/riscv/mm/fault.c
View File

@ -293,8 +293,8 @@ void handle_page_fault(struct pt_regs *regs)
if (unlikely(access_error(cause, vma))) {
vma_end_read(vma);
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
tsk->thread.bad_cause = SEGV_ACCERR;
bad_area_nosemaphore(regs, code, addr);
tsk->thread.bad_cause = cause;
bad_area_nosemaphore(regs, SEGV_ACCERR, addr);
return;
}

21
arch/riscv/mm/init.c
View File

@ -250,18 +250,19 @@ static void __init setup_bootmem(void)
kernel_map.va_pa_offset = PAGE_OFFSET - phys_ram_base;
/*
* memblock allocator is not aware of the fact that last 4K bytes of
* the addressable memory can not be mapped because of IS_ERR_VALUE
* macro. Make sure that last 4k bytes are not usable by memblock
* if end of dram is equal to maximum addressable memory. For 64-bit
* kernel, this problem can't happen here as the end of the virtual
* address space is occupied by the kernel mapping then this check must
* be done as soon as the kernel mapping base address is determined.
* Reserve physical address space that would be mapped to virtual
* addresses greater than (void *)(-PAGE_SIZE) because:
* - This memory would overlap with ERR_PTR
* - This memory belongs to high memory, which is not supported
*
* This is not applicable to 64-bit kernel, because virtual addresses
* after (void *)(-PAGE_SIZE) are not linearly mapped: they are
* occupied by kernel mapping. Also it is unrealistic for high memory
* to exist on 64-bit platforms.
*/
if (!IS_ENABLED(CONFIG_64BIT)) {
max_mapped_addr = __pa(~(ulong)0);
if (max_mapped_addr == (phys_ram_end - 1))
memblock_set_current_limit(max_mapped_addr - 4096);
max_mapped_addr = __va_to_pa_nodebug(-PAGE_SIZE);
memblock_reserve(max_mapped_addr, (phys_addr_t)-max_mapped_addr);
}
min_low_pfn = PFN_UP(phys_ram_base);