The simulator represents physical addresses using the address of its allocated buffer. That buffer can lie above the default ARCH_LOW_ADDRESS_LIMIT, preventing meaningful memblock_alloc_low() tests. Use the architecture override in asm/dma.h to place the limit halfway through the MEM_SIZE region registered by setup_memblock(). This leaves registered memory on both sides of the limit. PHYS_MEM_SIZE describes the larger backing allocation, rather than the registered region. Resolve the limit after allocating the buffer. The production allocator is unchanged. Assisted-by: Codex:GPT-6 Signed-off-by: Tianyi Chen --- tools/testing/memblock/asm/dma.h | 6 ++++++ tools/testing/memblock/tests/common.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/tools/testing/memblock/asm/dma.h b/tools/testing/memblock/asm/dma.h index 13ff8e5d22e..6607408dcf2 100644 --- a/tools/testing/memblock/asm/dma.h +++ b/tools/testing/memblock/asm/dma.h @@ -2,4 +2,10 @@ #ifndef _TOOLS_DMA_H #define _TOOLS_DMA_H +#include + +phys_addr_t dummy_physical_memory_low_limit(void); + +#define ARCH_LOW_ADDRESS_LIMIT dummy_physical_memory_low_limit() + #endif diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c index 3250c8e5124..17b95af216b 100644 --- a/tools/testing/memblock/tests/common.c +++ b/tools/testing/memblock/tests/common.c @@ -118,6 +118,12 @@ phys_addr_t dummy_physical_memory_base(void) return (phys_addr_t)memory_block.base; } +phys_addr_t dummy_physical_memory_low_limit(void) +{ + /* Split the MEM_SIZE region registered by setup_memblock(), not the buffer. */ + return dummy_physical_memory_base() + MEM_SIZE / 2; +} + static void usage(const char *prog) { BUILD_BUG_ON(ARRAY_SIZE(help_opts) != ARRAY_SIZE(long_opts) - 1); -- 2.55.0