riscv: kexec: Align the kexeced kernel entry

[ Upstream commit 1bfb2b618d52e59a4ef1896b46c4698ad2be66b7 ]

The current riscv boot protocol requires 2MB alignment for RV64
and 4MB alignment for RV32.

In KEXEC_FILE path, the elf_find_pbase() function should align
the kexeced kernel entry according to the requirement, otherwise
the kexeced kernel would silently BUG at the setup_vm().

Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Link: https://lore.kernel.org/r/20230906095817.364390-1-songshuaishuai@tinylab.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
index c08bb5c3b38578d26b07d30d6c2fcb2c91977863..b3b96ff46d1931f5916a6c16f8b83be8c5ee4dde 100644 (file)
--- a/arch/riscv/kernel/elf_kexec.c
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -98,7 +98,13 @@ static int elf_find_pbase(struct kimage *image, unsigned long kernel_len,
        kbuf.image = image;
        kbuf.buf_min = lowest_paddr;
        kbuf.buf_max = ULONG_MAX;
-       kbuf.buf_align = PAGE_SIZE;
+
+       /*
+        * Current riscv boot protocol requires 2MB alignment for
+        * RV64 and 4MB alignment for RV32
+        *
+        */
+       kbuf.buf_align = PMD_SIZE;
        kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
        kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE);
        kbuf.top_down = false;