[coreboot-gerrit] Patch set updated for coreboot: riscv: change payload() to pass the config string pointer as arg0

[Ronald G. Minnich (rminnich@gmail.com)]

Ronald G. Minnich (rminnich at gmail.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17254

-gerrit

commit 7fade81566bc26c920ee8ca86028e5657ddfe9de
Author: Ronald G. Minnich <rminnich at gmail.com>
Date:   Sun Nov 6 16:13:52 2016 -0800

    riscv: change payload() to pass the config string pointer as arg0
    
    The riscv 1.9 standard defines a textual config string to be passed
    to kernels and hypervisors. A pointer to this string is available
    at a platform-dependent location, default 0x100c on all extant platforms.
    
    Define a new config variable, ARCH_CONFIGSTRING_RISCV, to contain
    this location and change payload() arguments so arg0 is this pointer
    and arg1 is the pointer to the payload.
    
    Change-Id: I3be7f1712accf2d726704e4c970f22749d3c3f36
    Signed-off-by: Ronald G. Minnich <rminnich at gmail.com>
---
 src/arch/riscv/Kconfig   | 5 +++++
 src/arch/riscv/boot.c    | 7 +++++--
 src/arch/riscv/payload.S | 4 +++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/arch/riscv/Kconfig b/src/arch/riscv/Kconfig
index a30cb70..7c43da4 100644
--- a/src/arch/riscv/Kconfig
+++ b/src/arch/riscv/Kconfig
@@ -19,3 +19,8 @@ config ARCH_ROMSTAGE_RISCV
 config ARCH_RAMSTAGE_RISCV
 	bool
 	default n
+
+config ARCH_CONFIGSTRING_RISCV
+	hex "Location of pointer to RISCV config string"
+	default 0x100c
+	depends on ARCH_RISCV
diff --git a/src/arch/riscv/boot.c b/src/arch/riscv/boot.c
index ff1844e..0fa4d5f 100644
--- a/src/arch/riscv/boot.c
+++ b/src/arch/riscv/boot.c
@@ -22,12 +22,15 @@
 void arch_prog_run(struct prog *prog)
 {
 	void (*doit)(void *) = prog_entry(prog);
-	void riscvpayload(void *);
+	void riscvpayload(const char *configstring, void *payload);
+	uint32_t addr = *(uint32_t *)CONFIG_ARCH_CONFIGSTRING_RISCV;
+	const char *configstring = (const char *)(uintptr_t)addr;
 
 	if (ENV_RAMSTAGE && prog_type(prog) == PROG_PAYLOAD) {
+		printk(BIOS_SPEW, "Config string: '%s'\n", configstring);
 		initVirtualMemory();
 		printk(BIOS_SPEW, "OK, let's go\n");
-		riscvpayload(doit);
+		riscvpayload(configstring, doit);
 	}
 
 	doit(prog_entry_arg(prog));
diff --git a/src/arch/riscv/payload.S b/src/arch/riscv/payload.S
index 3261a80..e50a589 100644
--- a/src/arch/riscv/payload.S
+++ b/src/arch/riscv/payload.S
@@ -11,10 +11,12 @@
  * GNU General Public License for more details.
  */
 
+// "return" to a payload pointed to by a1 with
+// a pointer to the config string in a0.
 	.global riscvpayload
 riscvpayload:
 	/* Jump to a0 in S-mode */
-	mv t0,a0
+	mv t0,a1
 	csrw mepc, t0
 	csrr t0, mstatus
 	li t1, ~(3<<11)