Merge patch series "RISC-V: Fix a few kexec_file_load(2) failures"

Petr Tesarik <petrtesarik@huaweicloud.com> says:

From: Petr Tesarik <petr.tesarik.ext@huawei.com>

The kexec_file_load(2) syscall does not work at least in some kernel
builds. For details see the relevant section in this blog post:

https://sigillatum.tesarici.cz/2023-07-21-state-of-riscv64-kdump.html

This patch series handles an additional relocation types, removes the need
to implement a Global Offset Table (GOT) for the purgatory and fixes the
placement of initrd.

* b4-shazam-merge:
  riscv/kexec: load initrd high in available memory
  riscv/kexec: handle R_RISCV_CALL_PLT relocation type

Link: https://lore.kernel.org/r/cover.1690365011.git.petr.tesarik.ext@huawei.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/elf_kexec.c

@@ -281,7 +281,7 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf,
 		kbuf.buffer = initrd;
 		kbuf.bufsz = kbuf.memsz = initrd_len;
 		kbuf.buf_align = PAGE_SIZE;
-		kbuf.top_down = false;
+		kbuf.top_down = true;
 		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 		ret = kexec_add_buffer(&kbuf);
 		if (ret)
@@ -425,6 +425,7 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 		 * sym, instead of searching the whole relsec.
 		 */
 		case R_RISCV_PCREL_HI20:
+		case R_RISCV_CALL_PLT:
 		case R_RISCV_CALL:
 			*(u64 *)loc = CLEAN_IMM(UITYPE, *(u64 *)loc) |
 				 ENCODE_UJTYPE_IMM(val - addr);