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riscv: Get rid of CONFIG_PHYS_RAM_BASE in kernel physical address conversion

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The usage of CONFIG_PHYS_RAM_BASE for all kernel types was a mistake:
this value is implementation-specific and this breaks the genericity of
the RISC-V kernel.

Fix this by introducing a new variable phys_ram_base that holds this
value at runtime and use it in the kernel physical address conversion
macro. Since this value is used only for XIP kernels, evaluate it only if
CONFIG_XIP_KERNEL is set which in addition optimizes this macro for
standard kernels at compile-time.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Fixes: 44c9225729 ("RISC-V: enable XIP")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Alexandre Ghiti 2021-07-21 09:59:35 +02:00 committed by Palmer Dabbelt
parent a18b14d888
commit 6d7f91d914
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
2 changed files with 16 additions and 8 deletions
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7
arch/riscv/include/asm/page.h
View File

@ -103,6 +103,7 @@ struct kernel_mapping {
};
extern struct kernel_mapping kernel_map;
extern phys_addr_t phys_ram_base;
#ifdef CONFIG_64BIT
#define is_kernel_mapping(x) \
@ -113,9 +114,9 @@ extern struct kernel_mapping kernel_map;
#define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + kernel_map.va_pa_offset))
#define kernel_mapping_pa_to_va(y) ({ \
unsigned long _y = y; \
(_y >= CONFIG_PHYS_RAM_BASE) ? \
(void *)((unsigned long)(_y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET) : \
(void *)((unsigned long)(_y) + kernel_map.va_kernel_xip_pa_offset); \
(IS_ENABLED(CONFIG_XIP_KERNEL) && _y < phys_ram_base) ? \
(void *)((unsigned long)(_y) + kernel_map.va_kernel_xip_pa_offset) : \
(void *)((unsigned long)(_y) + kernel_map.va_kernel_pa_offset + XIP_OFFSET); \
})
#define __pa_to_va_nodebug(x) linear_mapping_pa_to_va(x)

17
arch/riscv/mm/init.c
View File

@ -36,6 +36,9 @@ EXPORT_SYMBOL(kernel_map);
#define kernel_map (*(struct kernel_mapping *)XIP_FIXUP(&kernel_map))
#endif
phys_addr_t phys_ram_base __ro_after_init;
EXPORT_SYMBOL(phys_ram_base);
#ifdef CONFIG_XIP_KERNEL
extern char _xiprom[], _exiprom[];
#endif
@ -160,7 +163,7 @@ static void __init setup_bootmem(void)
phys_addr_t vmlinux_end = __pa_symbol(&_end);
phys_addr_t vmlinux_start = __pa_symbol(&_start);
phys_addr_t __maybe_unused max_mapped_addr;
phys_addr_t dram_end;
phys_addr_t phys_ram_end;
#ifdef CONFIG_XIP_KERNEL
vmlinux_start = __pa_symbol(&_sdata);
@ -181,9 +184,12 @@ static void __init setup_bootmem(void)
#endif
memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
dram_end = memblock_end_of_DRAM();
phys_ram_end = memblock_end_of_DRAM();
#ifndef CONFIG_64BIT
#ifndef CONFIG_XIP_KERNEL
phys_ram_base = memblock_start_of_DRAM();
#endif
/*
* 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
@ -194,12 +200,12 @@ static void __init setup_bootmem(void)
* be done in create_kernel_page_table.
*/
max_mapped_addr = __pa(~(ulong)0);
if (max_mapped_addr == (dram_end - 1))
if (max_mapped_addr == (phys_ram_end - 1))
memblock_set_current_limit(max_mapped_addr - 4096);
#endif
min_low_pfn = PFN_UP(memblock_start_of_DRAM());
max_low_pfn = max_pfn = PFN_DOWN(dram_end);
min_low_pfn = PFN_UP(phys_ram_base);
max_low_pfn = max_pfn = PFN_DOWN(phys_ram_end);
dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
@ -558,6 +564,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
kernel_map.xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom);
phys_ram_base = CONFIG_PHYS_RAM_BASE;
kernel_map.phys_addr = (uintptr_t)CONFIG_PHYS_RAM_BASE;
kernel_map.size = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);