[coreboot-gerrit] Patch set updated for coreboot: [WIP] arch/riscv: Implement the SBI again

[Jonathan Neuschäfer (j.neuschaefer@gmx.net)]

Jonathan Neuschäfer (j.neuschaefer at gmx.net) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16119

-gerrit

commit 5070b001052c6eff07a5cee0a09d2845c3a588ac
Author: Jonathan Neuschäfer <j.neuschaefer at gmx.net>
Date:   Tue Aug 9 02:07:12 2016 +0200

    [WIP] arch/riscv: Implement the SBI again
    
    This is just a draft, so far. I didn't implement everything that Linux
    needs, and the SBI is still in flux:
    https://groups.google.com/a/groups.riscv.org/forum/#!topic/sw-dev/6oNhlW0OFKM
    
    Change-Id: I80e4fe508336d6428ca7136bc388fbc3cda4f1e4
    Signed-off-by: Jonathan Neuschäfer <j.neuschaefer at gmx.net>
---
 src/arch/riscv/Makefile.inc     |   1 +
 src/arch/riscv/include/vm.h     |   3 ++
 src/arch/riscv/sbi.S            | 103 ++++++++++++++++++++++++++++++++++++++++
 src/arch/riscv/virtual_memory.c |   2 +-
 4 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/src/arch/riscv/Makefile.inc b/src/arch/riscv/Makefile.inc
index 718aad9..4bab459 100644
--- a/src/arch/riscv/Makefile.inc
+++ b/src/arch/riscv/Makefile.inc
@@ -95,6 +95,7 @@ ramstage-y += stages.c
 ramstage-y += misc.c
 ramstage-y += boot.c
 ramstage-y += tables.c
+ramstage-y += sbi.S
 ramstage-y += \
 	$(top)/src/lib/memchr.c \
 	$(top)/src/lib/memcmp.c \
diff --git a/src/arch/riscv/include/vm.h b/src/arch/riscv/include/vm.h
index cd82b0a..985deec 100644
--- a/src/arch/riscv/include/vm.h
+++ b/src/arch/riscv/include/vm.h
@@ -70,4 +70,7 @@ void mstatus_init(void); // need to setup mstatus so we know we have virtual mem
 
 void flush_tlb(void);
 
+struct opaque;
+extern struct opaque sbi_page;
+
 #endif
diff --git a/src/arch/riscv/sbi.S b/src/arch/riscv/sbi.S
new file mode 100644
index 0000000..e4da3f3
--- /dev/null
+++ b/src/arch/riscv/sbi.S
@@ -0,0 +1,103 @@
+/*
+ * RISC-V supervisor binary interface (SBI) trampoline page
+ *
+ * Copyright 2016 Jonathan Neuschäfer <j.neuschaefer at gmx.net>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/encoding.h>
+
+.section ".text.sbi", "ax", %progbits
+
+/* align to a page boundary */
+.align RISCV_PGSHIFT
+
+.globl sbi_page
+sbi_page:
+
+	/*
+	 * None of the SBI entry points is located in the first half of the
+	 * page
+	 */
+	.skip 0x800
+
+	/* -2048: size_t sbi_hart_id(void); */
+	li a0, 0
+	jr ra
+	.align 4
+
+	/* -2032: size_t sbi_num_harts(viod); */
+	li a0, 1
+	jr ra
+	.align 4
+
+	/* -2016: sbi_query_memory (DEPRECATED!) */
+	ebreak
+	.align 4
+
+	/* -2000: int sbi_console_putchar(uint8_t ch); */
+	ebreak
+	.align 4
+
+	/* -1984: int sbi_console_putchar(uint8_t ch); */
+	li a0, -1	/* failure */
+	jr ra
+	.align 4
+
+	/* -1968: Not allocated */
+	ebreak
+	.align 4
+
+	/* -1952: int sbi_send_ipi(size_t hart_id); */
+	ebreak
+	.align 4
+
+	/* -1936: int bool sbi_clear_ipi(void); */
+	ebreak
+	.align 4
+
+	/* -1920: sbi_timebase (DEPRECATED!) */
+	ebreak
+	.align 4
+
+	/* -1904: void sbi_shutdown(void); */
+	ebreak
+	.align 4
+
+	/* -1888: sbi_set_timer (DEPRECATED!) */
+	ebreak
+	.align 4
+
+	/* -1872: int sbi_mask_interrupt(int which); */
+	ebreak
+	.align 4
+
+	/* -1856: int sbi_unmask_interrupt(int which); */
+	ebreak
+	.align 4
+
+	/* -1840: void sbi_remote_sfence_vm(const uintptr_t* harts,
+			size_t asid); */
+	ebreak
+	.align 4
+
+	/* -1824: void sbi_remote_sfence_vm_range(const uintptr_t* harts,
+			size_t asid, uintptr_t start, uintptr_t size); */
+	ebreak
+	.align 4
+
+	/* -1808: void sbi_remote_fence_i(const uintptr_t* harts); */
+	ebreak
+	.align 4
+
+/* Fill the remainder of the page */
+.align RISCV_PGSHIFT
diff --git a/src/arch/riscv/virtual_memory.c b/src/arch/riscv/virtual_memory.c
index 1987e08..ba83804 100644
--- a/src/arch/riscv/virtual_memory.c
+++ b/src/arch/riscv/virtual_memory.c
@@ -140,7 +140,7 @@ void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, uintptr_t pageTable
 
 	// map SBI at top of vaddr space
 	uintptr_t num_sbi_pages = 1; // only need to map a single page for sbi interface
-	uintptr_t sbiStartAddress = 0x2000; // the start of the sbi mapping
+	uintptr_t sbiStartAddress = (uintptr_t) &sbi_page;
 	uintptr_t sbiAddr = sbiStartAddress;
 	for (uintptr_t i = 0; i < num_sbi_pages; i++) {
 		uintptr_t idx = (1 << RISCV_PGLEVEL_BITS) - num_sbi_pages + i;