6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: John Harrison <John.C.Harrison@xxxxxxxxx> [ Upstream commit ec1455ce7e35a31289d2dbc1070b980538698921 ] There is a need to include the GuC log and other large binary objects in core dumps and via dmesg. So add a helper for dumping to a printer function via conversion to ASCII85 encoding. Another issue with dumping such a large buffer is that it can be slow, especially if dumping to dmesg over a serial port. So add a yield to prevent the 'task has been stuck for 120s' kernel hang check feature from firing. v2: Add a prefix to the output string. Fix memory allocation bug. v3: Correct a string size calculation and clean up a define (review feedback from Julia F). Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx> Reviewed-by: Julia Filipchuk <julia.filipchuk@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20241003004611.2323493-5-John.C.Harrison@xxxxxxxxx Stable-dep-of: 5dce85fecb87 ("drm/xe: Move the coredump registration to the worker thread") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/xe/xe_devcoredump.c | 87 +++++++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_devcoredump.h | 6 ++ 2 files changed, 93 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c index 2690f1d1cde4c..0884c49942fe6 100644 --- a/drivers/gpu/drm/xe/xe_devcoredump.c +++ b/drivers/gpu/drm/xe/xe_devcoredump.c @@ -6,6 +6,7 @@ #include "xe_devcoredump.h" #include "xe_devcoredump_types.h" +#include <linux/ascii85.h> #include <linux/devcoredump.h> #include <generated/utsrelease.h> @@ -315,3 +316,89 @@ int xe_devcoredump_init(struct xe_device *xe) } #endif + +/** + * xe_print_blob_ascii85 - print a BLOB to some useful location in ASCII85 + * + * The output is split to multiple lines because some print targets, e.g. dmesg + * cannot handle arbitrarily long lines. Note also that printing to dmesg in + * piece-meal fashion is not possible, each separate call to drm_puts() has a + * line-feed automatically added! Therefore, the entire output line must be + * constructed in a local buffer first, then printed in one atomic output call. + * + * There is also a scheduler yield call to prevent the 'task has been stuck for + * 120s' kernel hang check feature from firing when printing to a slow target + * such as dmesg over a serial port. + * + * TODO: Add compression prior to the ASCII85 encoding to shrink huge buffers down. + * + * @p: the printer object to output to + * @prefix: optional prefix to add to output string + * @blob: the Binary Large OBject to dump out + * @offset: offset in bytes to skip from the front of the BLOB, must be a multiple of sizeof(u32) + * @size: the size in bytes of the BLOB, must be a multiple of sizeof(u32) + */ +void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, + const void *blob, size_t offset, size_t size) +{ + const u32 *blob32 = (const u32 *)blob; + char buff[ASCII85_BUFSZ], *line_buff; + size_t line_pos = 0; + +#define DMESG_MAX_LINE_LEN 800 +#define MIN_SPACE (ASCII85_BUFSZ + 2) /* 85 + "\n\0" */ + + if (size & 3) + drm_printf(p, "Size not word aligned: %zu", size); + if (offset & 3) + drm_printf(p, "Offset not word aligned: %zu", size); + + line_buff = kzalloc(DMESG_MAX_LINE_LEN, GFP_KERNEL); + if (IS_ERR_OR_NULL(line_buff)) { + drm_printf(p, "Failed to allocate line buffer: %pe", line_buff); + return; + } + + blob32 += offset / sizeof(*blob32); + size /= sizeof(*blob32); + + if (prefix) { + strscpy(line_buff, prefix, DMESG_MAX_LINE_LEN - MIN_SPACE - 2); + line_pos = strlen(line_buff); + + line_buff[line_pos++] = ':'; + line_buff[line_pos++] = ' '; + } + + while (size--) { + u32 val = *(blob32++); + + strscpy(line_buff + line_pos, ascii85_encode(val, buff), + DMESG_MAX_LINE_LEN - line_pos); + line_pos += strlen(line_buff + line_pos); + + if ((line_pos + MIN_SPACE) >= DMESG_MAX_LINE_LEN) { + line_buff[line_pos++] = '\n'; + line_buff[line_pos++] = 0; + + drm_puts(p, line_buff); + + line_pos = 0; + + /* Prevent 'stuck thread' time out errors */ + cond_resched(); + } + } + + if (line_pos) { + line_buff[line_pos++] = '\n'; + line_buff[line_pos++] = 0; + + drm_puts(p, line_buff); + } + + kfree(line_buff); + +#undef MIN_SPACE +#undef DMESG_MAX_LINE_LEN +} diff --git a/drivers/gpu/drm/xe/xe_devcoredump.h b/drivers/gpu/drm/xe/xe_devcoredump.h index e2fa65ce09322..a4eebc285fc83 100644 --- a/drivers/gpu/drm/xe/xe_devcoredump.h +++ b/drivers/gpu/drm/xe/xe_devcoredump.h @@ -6,6 +6,9 @@ #ifndef _XE_DEVCOREDUMP_H_ #define _XE_DEVCOREDUMP_H_ +#include <linux/types.h> + +struct drm_printer; struct xe_device; struct xe_sched_job; @@ -23,4 +26,7 @@ static inline int xe_devcoredump_init(struct xe_device *xe) } #endif +void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, + const void *blob, size_t offset, size_t size); + #endif -- 2.43.0
