Changeset cfdeedc in mainline for boot/arch/riscv64

Timestamp:

2018-10-21T23:12:23Z (7 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

bf05c74

Parents:

d59718e

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-10-21 22:53:48)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-10-21 23:12:23)

Message:

Keep kernel in ELF format

By keeping kernel in an ELF file (instead of converting it to
a flat binary), we can use the information it contains, like
symbol table and debug info.

We can also later implement more advanced functionality, like
loading kernel at multiple discontiguous blocks, or loading
a position-independent kernel at a randomized address.

Currently the functionality is quite restricted, to keep changes
to a minimum. Code in boot/generic/src/kernel.c validates that
the kernel image was built with the same addresses as the boot
loader uses, giving an extra level of sanity checking compared
to a flat binary.

Location:

boot/arch/riscv64

Files:

• Makefile.inc (modified) (2 diffs)
• include/arch/asm.h (modified) (1 diff)
• src/asm.S (modified) (1 diff)
• src/main.c (modified) (2 diffs)

boot/arch/riscv64/Makefile.inc

@@ -30 +30 @@
 BFD_OUTPUT = $(BFD_NAME)
 BFD_ARCH = riscv
-BFD = binary
 
 BITS = 64
@@ -51 +50 @@
         generic/src/gzip.c \
         generic/src/tar.c \
+        generic/src/kernel.c \
         generic/src/payload.c

boot/arch/riscv64/include/arch/asm.h

@@ -36 +36 @@
 extern char pt_page[];
 
-extern _Noreturn void jump_to_kernel(uintptr_t);
+extern _Noreturn void jump_to_kernel(uintptr_t, uintptr_t);
 
 #endif

boot/arch/riscv64/src/asm.S

@@ -125 +125 @@
         csrw mstatus, t0
 
-        li ra, PA2KA(BOOT_OFFSET)
+        /* Entry point address is in a1. */
+        mv ra, a1
         csrw mepc, ra
 

boot/arch/riscv64/src/main.c

@@ -42 +42 @@
 #include <halt.h>
 #include <payload.h>
+#include <kernel.h>
 
 static bootinfo_t bootinfo;
@@ -88 +89 @@
         extract_payload(&bootinfo.taskmap, load_addr, end, kernel_addr, NULL);
 
+        uintptr_t entry = check_kernel(load_addr);
+
         printf("Booting the kernel...\n");
-        jump_to_kernel(PA2KA(&bootinfo));
+        jump_to_kernel(PA2KA(&bootinfo), entry);
 }