5.15-stable review patch. If anyone has any objections, please let me know.
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From: Simon Schuster schuster.simon@siemens-energy.com
[ Upstream commit a20b83cf45be2057f3d073506779e52c7fa17f94 ]
On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM.
This can in turn cause kernel-level paging failures, e.g.:
[ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]---
This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.
Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com Signed-off-by: Andreas Oetken andreas.oetken@siemens-energy.com Signed-off-by: Dinh Nguyen dinguyen@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/nios2/kernel/setup.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c index 40bc8fb75e0b5..e2fc4b59d93ea 100644 --- a/arch/nios2/kernel/setup.c +++ b/arch/nios2/kernel/setup.c @@ -147,6 +147,20 @@ static void __init find_limits(unsigned long *min, unsigned long *max_low, *max_high = PFN_DOWN(memblock_end_of_DRAM()); }
+static void __init adjust_lowmem_bounds(void) +{ + phys_addr_t block_start, block_end; + u64 i; + phys_addr_t memblock_limit = 0; + + for_each_mem_range(i, &block_start, &block_end) { + if (block_end > memblock_limit) + memblock_limit = block_end; + } + + memblock_set_current_limit(memblock_limit); +} + void __init setup_arch(char **cmdline_p) { console_verbose(); @@ -160,6 +174,7 @@ void __init setup_arch(char **cmdline_p) /* Keep a copy of command line */ *cmdline_p = boot_command_line;
+ adjust_lowmem_bounds(); find_limits(&min_low_pfn, &max_low_pfn, &max_pfn); max_mapnr = max_low_pfn;