arch/x86/boot.c: Pass arguments when running programs

Payloads can use coreboot tables passed on via arguments instead of
via a pointer in lower memory.

Stages can make use of the argument to pass on information.

Change-Id: Ie0f44e9e1992221e02c49d0492cdd2a3d9013560
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36143
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/x86/boot.c

@@ -30,13 +30,12 @@ int payload_arch_usable_ram_quirk(uint64_t start, uint64_t size)
 
 void arch_prog_run(struct prog *prog)
 {
-	__asm__ volatile (
 #ifdef __x86_64__
-		"jmp  *%%rdi\n"
+	void (*doit)(void *arg);
 #else
-		"jmp  *%%edi\n"
+	/* Ensure the argument is pushed on the stack. */
+	asmlinkage void (*doit)(void *arg);
 #endif
-
+	doit = prog_entry(prog);
-		:: "D"(prog_entry(prog))
+	doit(prog_entry_arg(prog));
-	);
 }