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authorRonald G. Minnich <rminnich@gmail.com>2016-11-12 07:31:16 -0800
committerRonald G. Minnich <rminnich@gmail.com>2016-11-14 01:09:12 +0100
commit3d302b03f46fa6ed5927cdc2ef9f53b9ce0262ae (patch)
tree4d509bb2bbf0cdb62ba7cd3b035b22416511afdb
parent42c1e43cb16b26925611335bdc97808dae745af5 (diff)
downloadcoreboot-3d302b03f46fa6ed5927cdc2ef9f53b9ce0262ae.tar.xz
riscv: add a variable to control trap management
This variable can be set in a debugger (e.g. Spike) to finely control which traps go to coreboot and which go to the supervisor. Change-Id: I292264c15f002c41cf8d278354d8f4c0efbd0895 Signed-off-by: Ronald G. Minnich <rminnich@gmail.com> Reviewed-on: https://review.coreboot.org/17404 Tested-by: build bot (Jenkins) Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
-rw-r--r--src/arch/riscv/virtual_memory.c26
1 files changed, 16 insertions, 10 deletions
diff --git a/src/arch/riscv/virtual_memory.c b/src/arch/riscv/virtual_memory.c
index 999d73cec8..6d93bd0def 100644
--- a/src/arch/riscv/virtual_memory.c
+++ b/src/arch/riscv/virtual_memory.c
@@ -23,6 +23,21 @@
#include <vm.h>
#include <symbols.h>
+/* Delegate controls which traps are delegated to the payload. If you
+ * wish to temporarily disable some or all delegation you can, in a
+ * debugger, set it to a different value (e.g. 0 to have all traps go
+ * to M-mode). In practice, this variable has been a lifesaver. It is
+ * still not quite determined which delegation might by unallowed by
+ * the spec so for now we enumerate and set them all. */
+static int delegate = 0
+ | (1 << CAUSE_MISALIGNED_FETCH)
+ | (1 << CAUSE_FAULT_FETCH)
+ | (1 << CAUSE_ILLEGAL_INSTRUCTION)
+ | (1 << CAUSE_BREAKPOINT)
+ | (1 << CAUSE_FAULT_LOAD)
+ | (1 << CAUSE_FAULT_STORE)
+ | (1 << CAUSE_USER_ECALL)
+ ;
pte_t* root_page_table;
/* Indent the following text by 2*level spaces */
@@ -223,16 +238,7 @@ void mstatus_init(void)
clear_csr(mip, MIP_MSIP);
set_csr(mie, MIP_MSIP);
- /* Configure which exception causes are delegated to supervisor mode */
- set_csr(medeleg, (1 << CAUSE_MISALIGNED_FETCH)
- | (1 << CAUSE_FAULT_FETCH)
- | (1 << CAUSE_ILLEGAL_INSTRUCTION)
- | (1 << CAUSE_BREAKPOINT)
- | (1 << CAUSE_FAULT_LOAD)
- | (1 << CAUSE_FAULT_STORE)
- | (1 << CAUSE_USER_ECALL)
- );
-
+ set_csr(medeleg, delegate);
/* Enable all user/supervisor-mode counters */
/* We'll turn these on once lowrisc gets their bitstream up to