Commit graph

20 commits

Author SHA1 Message Date
Heinrich Schuchardt
f6431e8fb3 riscv: show code leading to exception
To make analyzing exceptions easier output the code that leads to it.
We already do the same on the ARM platform.

Here is an example:

    => exception ebreak
    Unhandled exception: Breakpoint
    EPC: 000000008ff5d50e RA: 000000008ff5d62c TVAL: 0000000000000000
    EPC: 000000008020b50e RA: 000000008020b62c reloc adjusted

    Code: 2785 0693 07a0 dce3 fef6 47a5 d563 00e7 (9002)

To disassemble the code we can use the decodecode script:

    $ echo 'Code: 2785 0693 07a0 dce3 fef6 47a5 d563 00e7 (9002)' | \
      CROSS_COMPILE=riscv64-linux-gnu- scripts/decodecode

    Code: 2785 0693 07a0 dce3 fef6 47a5 d563 00e7 (9002)
    All code
    ========
       0:   2785                    addiw   a5,a5,1
       2:   07a00693                li      a3,122
       6:   fef6dce3                bge     a3,a5,0xfffffffffffffffe
       a:   47a5                    li      a5,9
       c:   00e7d563                bge     a5,a4,0x16
      10:*  9002                    ebreak         <-- trapping instruction
            ...

    Code starting with the faulting instruction
    ===========================================
       0:   9002                    ebreak
            ...

As it is not always clear if the first 16 bits are at the start or in the
middle of a 32bit instruction it may become necessary to strip the first
u16 from the output before calling decodecode to get the correct
disassembled code.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
2021-09-07 10:34:29 +08:00
Simon Glass
401d1c4f5d common: Drop asm/global_data.h from common header
Move this out of the common header and include it only where needed.  In
a number of cases this requires adding "struct udevice;" to avoid adding
another large header or in other cases replacing / adding missing header
files that had been pulled in, very indirectly.   Finally, we have a few
cases where we did not need to include <asm/global_data.h> at all, so
remove that include.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
2021-02-02 15:33:42 -05:00
Heinrich Schuchardt
c353f2b845 riscv: reset after crash
If an exception occurs on ARM or x86, we call panic() which will try to
reset the board. Do the same on RISC-V.

To avoid -Werror=format-zero-length move a '\n' to the string passed to
panic. We don't need a message here as depending on CONFIG_PANIC_HANG we
will either see

    ### ERROR ### Please RESET the board ###

or

    resetting ...

as next message.

Reviewed-by: Rick Chen <rick@andestech.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-12-14 15:16:41 +08:00
Tom Rini
b7e7831e5d Merge branch 'next'
Bring in the assorted changes that have been staged in the 'next' branch
prior to release.

Signed-off-by: Tom Rini <trini@konsulko.com>
2020-10-05 14:10:59 -04:00
Sean Anderson
85768134b4 riscv: Ensure gp is NULL or points to valid data
This ensures constructs like `if (gd & gd->...) { ... }` work when
accessing the global data pointer. Without this change, it was possible for
a very early trap to cause _exit_trap to directly or indirectly (through
printf) to read arbitrary memory. This could cause a second trap,
preventing show_regs from being printed.

printf (and specifically puts) uses gd to determine what function to print
with. These functions in turn use gd to find the serial device, etc.
However, before accessing gd, puts first checks to see if it is non-NULL.
This indicates an existing (perhaps undocumented) assumption that either gd
is NULL or it is completely valid.

Before this patch, gd either points to unexpected data (because it retains
the value it did from the prior-stage) or points to uninitialized data
(because it has not yet been initialized by board_init_f_init_reserve)
until the hart has acquired available_harts_lock. This can cause two
problems, depending on the value of gd->flags. If GD_FLG_SERIAL_READY is
unset, then some garbage data will be printed to stdout, but there will not
be a second trap. However, if GD_FLG_SERIAL_READY is set, then puts will
try to print with serial_puts, which will likely cause a second trap.

After this patch, gd is zero up until either a hart has set it in
wait_for_gd_init, or until it is set by arch_init_gd. This prevents its
usage before its data is initialized because both handle_trap and puts
ensure that gd is nonzero before using it. After gd has been set, it is OK
to access it because its data has been cleared (and so flags is valid).

XIP cannot use locks because flash is not writable. This leaves it
vulnerable to the same class of bugs regarding already-pending IPIs as
before this series. Fixing that would require finding another method of
synchronization, which is outside the scope of this series.

Fixes: 7c6ca03eae ("riscv: additional crash information")
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2020-09-30 08:54:52 +08:00
Heinrich Schuchardt
c48e9f310b riscv: restore global data pointer in trap handler
The gp register is used to store U-Boot's global data pointer. We should
not assume that an UEFI application leaves the gp register unchanged as
the UEFI specifications does not define who is the owner of the gp and tp
registers.

So the following sequence should be followed in the trap handler:

* save the caller's gp register
* restore the global data pointer
* serve interrupts or print crash dump and reset
* restore the caller's gp register

Cc: Abner Chang <abner.chang@hpe.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2020-09-28 12:20:19 +02:00
Heinrich Schuchardt
7c6ca03eae riscv: additional crash information
If an exception occurs, the relocated program counter and return address
are required for an analysis.

With this patch you get:

    => exception undefined

    Unhandled exception: Illegal instruction
    EPC: 0000000080595908 RA: 000000008059c0c6 TVAL: 000000008030c01e
    EPC: 0000000080007908 RA: 000000008000e0c6 reloc adjusted

We can use the relocated addresses to find the involved functions in
u.boot.map:

    .text.do_undefined
                0x0000000080007908        0x8 cmd/built-in.o
    .text.cmd_process
                0x000000008000dfcc      0x11a common/built-in.o
                0x000000008000dfcc                cmd_process

If an exception occurs in an UEFI binary additionally the load addresses of
the UEFI binaries are needed. With this patch:

    => setenv efi_selftest exception
    => bootefi selftest

    Unhandled exception: Illegal instruction
    EPC: 000000008042e18a RA: 000000008042e18a TVAL: 000000008030c01e
    EPC: 000000007fea018a RA: 000000007fea018a reloc adjusted

    UEFI image [0x0000000000000000:0xffffffffffffffff] '/\selftest'
    UEFI image [0x000000008042e000:0x000000008042e43f] pc=0x18a '/bug.efi'

The value pc=0x18a matches the position of the illegal instruction in
efi_selftest_miniapp_exception.efi (loaded as /bug.efi);

    asm volatile (".word 0xffffffff\n");

    00000180   93 85 C5 11  1C 64 22 85  82 97 FF FF  FF FF 1C 64

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Tested-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2020-08-14 14:39:41 +08:00
Sean Anderson
fd1f6e9a0b riscv: Add option to print registers on exception
When debugging, it can be helpful to see more information about an
unhandled exception. This patch adds an option to view the registers at
the time of the trap, similar to the linux output on a kernel panic.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2020-02-10 14:51:08 +08:00
Simon Glass
db41d65a97 common: Move hang() to the same header as panic()
At present panic() is in the vsprintf.h header file. That does not seem
like an obvious choice for hang(), even though it relates to panic(). So
let's put hang() in its own header.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Migrate a few more files]
Signed-off-by: Tom Rini <trini@konsulko.com>
2020-01-17 17:53:40 -05:00
Simon Glass
c30b7adbca common: Move interrupt functions into a new header
These functions do not use driver model but are fairly widely used in
U-Boot. But it is not clear that they will use driver model anytime soon,
so we don't want to label them as 'legacy'.

Move them to a new irq_func.h header file. Avoid the name 'irq.h' since it
is widely used in U-Boot already.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2019-12-02 18:25:00 -05:00
Lukas Auer
0c85c113c4 riscv: clarify error message on undefined exceptions
Undefined exceptions are treated as reserved. This is not clearly
communicated to the user. Adjust the error message to clarify that a
reserved exception has occurred and add additional details.

Fixes: e8b522b ("riscv: treat undefined exception codes as reserved")
Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2019-01-15 09:36:31 +08:00
Bin Meng
7f5d35a547 riscv: Adjust the _exit_trap() position to come before handle_trap()
With this change, we can avoid a forward declaration.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
2018-12-18 09:56:27 +08:00
Anup Patel
d2db2a8fa4 riscv: Add kconfig option to run U-Boot in S-mode
This patch adds kconfig option RISCV_SMODE to run U-Boot in
S-mode. When this opition is enabled we use s<xyz> CSRs instead
of m<xyz> CSRs.

It is important to note that there is no equivalent S-mode CSR
for misa and mhartid CSRs so we expect M-mode runtime firmware
(BBL or equivalent) to emulate misa and mhartid CSR read.

In-future, we will have more patches to avoid accessing misa and
mhartid CSRs from S-mode.

Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
2018-12-05 14:13:53 +08:00
Lukas Auer
c93a1c8185 riscv: hang on unhandled exceptions
Hang on unhandled exceptions to prevent execution in a faulty state.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2018-11-26 13:57:30 +08:00
Lukas Auer
e8b522b1df riscv: treat undefined exception codes as reserved
Undefined exception codes currently lead to an out-of-bounds array
access. Prevent this by treating undefined exception codes as
"reserved".

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2018-11-26 13:57:30 +08:00
Lukas Auer
5a441736b7 riscv: complete the list of exception codes
Only the first four exception codes are defined. Add the missing
exception codes from the definition in RISC-V Privileged Architecture
Version 1.10.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2018-11-26 13:57:30 +08:00
Lukas Auer
b2c860c6dc riscv: fix use of incorrectly sized variables
The RISC-V arch incorrectly uses 32-bit instead of 64-bit variables in
several places. Fix this.
In addition, BITS_PER_LONG is set to 64 on RV64I systems.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2018-11-26 13:57:29 +08:00
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Rick Chen
22e8c0f02b riscv: checkpatch: Fix static const char * array declarations
It is reported by checkpatch.pl
WARNING: static const char * array
should probably be static const char * const

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
2018-03-30 13:13:22 +08:00
Rick Chen
8bbb2909cb riscv: nx25: lib: Add relative lib funcs to support RISC-V
Add makefile, interrupts.c and boot.c,... functions
to support RISC-V arch.

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Cc: Padmarao Begari <Padmarao.Begari@microsemi.com>
2018-01-12 08:05:12 -05:00