bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

riscv: Move kernel mapping outside of linear mapping

Browse Source 
This is a preparatory patch for relocatable kernel and sv48 support.

The kernel used to be linked at PAGE_OFFSET address therefore we could use
the linear mapping for the kernel mapping. But the relocated kernel base
address will be different from PAGE_OFFSET and since in the linear mapping,
two different virtual addresses cannot point to the same physical address,
the kernel mapping needs to lie outside the linear mapping so that we don't
have to copy it at the same physical offset.

The kernel mapping is moved to the last 2GB of the address space, BPF
is now always after the kernel and modules use the 2GB memory range right
before the kernel, so BPF and modules regions do not overlap. KASLR
implementation will simply have to move the kernel in the last 2GB range
and just take care of leaving enough space for BPF.

In addition, by moving the kernel to the end of the address space, both
sv39 and sv48 kernels will be exactly the same without needing to be
relocated at runtime.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
[Palmer: Squash the STRICT_RWX fix, and a !MMU fix]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Alexandre Ghiti
2021-04-11 12:41:44 -04:00
committed by Palmer Dabbelt
parent 8a07ac39f8
commit 2bfc6cd81b
12 changed files with 182 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
arch/riscv/include/asm/page.h
View File

@@ -90,15 +90,37 @@ typedef struct page *pgtable_t;
#ifdef CONFIG_MMU
extern unsigned long va_pa_offset;
#ifdef CONFIG_64BIT
extern unsigned long va_kernel_pa_offset;
#endif
extern unsigned long pfn_base;
#define ARCH_PFN_OFFSET (pfn_base)
#else
#define va_pa_offset 0
#ifdef CONFIG_64BIT
#define va_kernel_pa_offset 0
#endif
#define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
#endif /* CONFIG_MMU */
#define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset))
#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset)
#ifdef CONFIG_64BIT
extern unsigned long kernel_virt_addr;
#define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_pa_offset))
#define kernel_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_kernel_pa_offset))
#define __pa_to_va_nodebug(x) linear_mapping_pa_to_va(x)
#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset)
#define kernel_mapping_va_to_pa(x) ((unsigned long)(x) - va_kernel_pa_offset)
#define __va_to_pa_nodebug(x) ({ \
unsigned long _x = x; \
(_x < kernel_virt_addr) ? \
linear_mapping_va_to_pa(_x) : kernel_mapping_va_to_pa(_x); \
})
#else
#define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset))
#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset)
#endif
#ifdef CONFIG_DEBUG_VIRTUAL
extern phys_addr_t __virt_to_phys(unsigned long x);