From: Han Gao Date: Sun, 7 Jun 2026 02:17:58 +0000 (-0600) Subject: riscv: kexec_file: Constrain segment placement to direct map X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b67a1ee0db0094c6cc158b087be6c334ad881a41;p=thirdparty%2Fkernel%2Flinux.git riscv: kexec_file: Constrain segment placement to direct map When kexec_file_load places segments with buf_max=ULONG_MAX and top_down=true, they land at the highest available physical addresses. On RISC-V the size of the linear mapping is determined by the active VM mode: SV39 caps the direct map at roughly 128GB, while SV48/SV57 extend the range substantially further. When the installed physical memory exceeds the direct map size of the active mode, top-down placement puts DTB/initrd at physical addresses outside the linearly mapped region. The kexec'd kernel cannot reach them during early boot, triggering a page fault at memcmp in start_kernel. Fix by constraining buf_max to PFN_PHYS(max_low_pfn), which reflects the runtime direct map boundary for the active VM mode (SV39/SV48/ SV57). This keeps all kexec segments within the linearly mapped region while preserving the upstream top_down allocation strategy. Signed-off-by: Han Gao Link: https://patch.msgid.link/20260519170641.123517-1-gaohan@iscas.ac.cn Signed-off-by: Paul Walmsley --- diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c index 54e2d9552e93..59d4bbc848a8 100644 --- a/arch/riscv/kernel/machine_kexec_file.c +++ b/arch/riscv/kernel/machine_kexec_file.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -266,7 +267,7 @@ int load_extra_segments(struct kimage *image, unsigned long kernel_start, kbuf.image = image; kbuf.buf_min = kernel_start + kernel_len; - kbuf.buf_max = ULONG_MAX; + kbuf.buf_max = PFN_PHYS(max_low_pfn); #ifdef CONFIG_CRASH_DUMP /* Add elfcorehdr */