From 14faee6916bc973b9fdb816c5f4a45096e3f645a Mon Sep 17 00:00:00 2001 From: Jessica Clarke Date: Sun, 21 Nov 2021 17:30:22 +0000 Subject: [PATCH] lib: sbi: Improve fatal error handling BUG and BUG_ON are not informative and are rather lazy interfaces, only telling the user that something went wrong in a given function, but not what, requiring the user to find the sources corresponding to their firmware (which may not be available) and figure out how that BUG(_ON) was hit. Even SBI_ASSERT in its current form, which does include the condition that triggered it in the output, isn't necessarily very informative. In some cases, the error may be fixable by the user, but they need to know the problem in order to have any hope of fixing it. It's also a nuisance for developers, whose development trees may have changed significantly since the release in question being used, and so line numbers can make it harder for them to understand which error case a user has hit. This patch introduces a new sbi_panic function which is printf-like, allowing detailed error messages to be printed to the console. BUG and BUG_ON are removed, since the former is just a worse form of sbi_panic and the latter is a worse version of SBI_ASSERT. Finally, SBI_ASSERT is augmented to take a set of arguments to pass to sbi_panic on failure, used like so (sbi_boot_print_hart's current error case, which currently manually calls sbi_printf and sbi_hart_hang): SBI_ASSERT(xlen >= 1, ("Error %d getting MISA XLEN\n", xlen)); The existing users of BUG are replaced with calls to sbi_panic along with informative error messages. BUG_ON and SBI_ASSERT were unused (and, in the case of SBI_ASSERT, remain unused). Many existing users of sbi_hart_hang should be converted to use either sbi_panic or SBI_ASSERT after this commit. Signed-off-by: Jessica Clarke Reviewed-by: Anup Patel Reviewed-by: Xiang W Reviewed-by: Atish Patra --- include/sbi/sbi_console.h | 23 +++++------------------ lib/sbi/riscv_asm.c | 7 ++++--- lib/sbi/sbi_console.c | 14 ++++++++++++++ platform/generic/sifive_fu740.c | 1 + 4 files changed, 24 insertions(+), 21 deletions(-) diff --git a/include/sbi/sbi_console.h b/include/sbi/sbi_console.h index 28b4a79..e15b55d 100644 --- a/include/sbi/sbi_console.h +++ b/include/sbi/sbi_console.h @@ -11,7 +11,6 @@ #define __SBI_CONSOLE_H__ #include -#include struct sbi_console_device { /** Name of the console device */ @@ -44,6 +43,8 @@ int __printf(1, 2) sbi_printf(const char *format, ...); int __printf(1, 2) sbi_dprintf(const char *format, ...); +void __printf(1, 2) __attribute__((noreturn)) sbi_panic(const char *format, ...); + const struct sbi_console_device *sbi_console_get_device(void); void sbi_console_set_device(const struct sbi_console_device *dev); @@ -52,23 +53,9 @@ struct sbi_scratch; int sbi_console_init(struct sbi_scratch *scratch); -#define BUG() do { \ - sbi_printf("BUG: failure at %s:%d/%s()!\n", \ - __FILE__, __LINE__, __func__); \ - sbi_hart_hang(); \ -} while (0) - -#define BUG_ON(cond) do { \ - if (cond) \ - BUG(); \ -} while (0) - -#define SBI_ASSERT(cond) do { \ - if (!(cond)) { \ - sbi_printf("ASSERT: %s:%d/%s(): Assertion `%s` failed.\n", \ - __FILE__,__LINE__,__func__, #cond);\ - sbi_hart_hang(); \ - } \ +#define SBI_ASSERT(cond, args) do { \ + if (unlikely(!(cond))) \ + sbi_panic args; \ } while (0) #endif diff --git a/lib/sbi/riscv_asm.c b/lib/sbi/riscv_asm.c index 1642ac6..2e2e148 100644 --- a/lib/sbi/riscv_asm.c +++ b/lib/sbi/riscv_asm.c @@ -76,7 +76,8 @@ void misa_string(int xlen, char *out, unsigned int out_sz) out[pos++] = '8'; break; default: - BUG(); + sbi_panic("%s: Unknown misa.MXL encoding %d", + __func__, xlen); return; } } @@ -145,7 +146,7 @@ unsigned long csr_read_num(int csr_num) #endif default: - BUG(); + sbi_panic("%s: Unknown CSR %#x", __func__, csr_num); break; }; @@ -213,7 +214,7 @@ void csr_write_num(int csr_num, unsigned long val) switchcase_csr_write_16(CSR_MHPMEVENT16, val) default: - BUG(); + sbi_panic("%s: Unknown CSR %#x", __func__, csr_num); break; }; diff --git a/lib/sbi/sbi_console.c b/lib/sbi/sbi_console.c index 29eede3..34c843d 100644 --- a/lib/sbi/sbi_console.c +++ b/lib/sbi/sbi_console.c @@ -9,6 +9,7 @@ #include #include +#include #include #include @@ -397,6 +398,19 @@ int sbi_dprintf(const char *format, ...) return retval; } +void sbi_panic(const char *format, ...) +{ + va_list args; + + spin_lock(&console_out_lock); + va_start(args, format); + print(NULL, NULL, format, args); + va_end(args); + spin_unlock(&console_out_lock); + + sbi_hart_hang(); +} + const struct sbi_console_device *sbi_console_get_device(void) { return console_dev; diff --git a/platform/generic/sifive_fu740.c b/platform/generic/sifive_fu740.c index 3152152..333b3fb 100644 --- a/platform/generic/sifive_fu740.c +++ b/platform/generic/sifive_fu740.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include -- 2.7.4