4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> [ Upstream commit 38bb8d77d0b932a0773b5de2ef42479409314f96 ] PT uses page sized ToPA tables, where the ToPA table resides at the bottom and its driver-specific metadata taking up a few words at the top of the page. The split is currently calculated manually and needs to be redone every time a field is added to or removed from the metadata structure. Also, the 32-bit version can be made smaller. By splitting the table and metadata into separate structures, we are making the compiler figure out the division of the page. Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Vince Weaver <vincent.weaver@xxxxxxxxx> Link: http://lkml.kernel.org/r/20190821124727.73310-5-alexander.shishkin@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Stable-dep-of: ad97196379d0 ("perf/x86/intel/pt: Fix a topa_entry base address calculation") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/x86/events/intel/pt.c | 93 ++++++++++++++++++++++++-------------- 1 file changed, 60 insertions(+), 33 deletions(-) diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 5dff4548b0875..1fe74019ee3c8 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -546,16 +546,8 @@ static void pt_config_buffer(void *buf, unsigned int topa_idx, wrmsrl(MSR_IA32_RTIT_OUTPUT_MASK, reg); } -/* - * Keep ToPA table-related metadata on the same page as the actual table, - * taking up a few words from the top - */ - -#define TENTS_PER_PAGE (((PAGE_SIZE - 40) / sizeof(struct topa_entry)) - 1) - /** - * struct topa - page-sized ToPA table with metadata at the top - * @table: actual ToPA table entries, as understood by PT hardware + * struct topa - ToPA metadata * @list: linkage to struct pt_buffer's list of tables * @phys: physical address of this page * @offset: offset of the first entry in this table in the buffer @@ -563,7 +555,6 @@ static void pt_config_buffer(void *buf, unsigned int topa_idx, * @last: index of the last initialized entry in this table */ struct topa { - struct topa_entry table[TENTS_PER_PAGE]; struct list_head list; u64 phys; u64 offset; @@ -571,8 +562,39 @@ struct topa { int last; }; +/* + * Keep ToPA table-related metadata on the same page as the actual table, + * taking up a few words from the top + */ + +#define TENTS_PER_PAGE \ + ((PAGE_SIZE - sizeof(struct topa)) / sizeof(struct topa_entry)) + +/** + * struct topa_page - page-sized ToPA table with metadata at the top + * @table: actual ToPA table entries, as understood by PT hardware + * @topa: metadata + */ +struct topa_page { + struct topa_entry table[TENTS_PER_PAGE]; + struct topa topa; +}; + +static inline struct topa_page *topa_to_page(struct topa *topa) +{ + return container_of(topa, struct topa_page, topa); +} + +static inline struct topa_page *topa_entry_to_page(struct topa_entry *te) +{ + return (struct topa_page *)((unsigned long)te & PAGE_MASK); +} + /* make -1 stand for the last table entry */ -#define TOPA_ENTRY(t, i) ((i) == -1 ? &(t)->table[(t)->last] : &(t)->table[(i)]) +#define TOPA_ENTRY(t, i) \ + ((i) == -1 \ + ? &topa_to_page(t)->table[(t)->last] \ + : &topa_to_page(t)->table[(i)]) #define TOPA_ENTRY_SIZE(t, i) (sizes(TOPA_ENTRY((t), (i))->size)) /** @@ -585,27 +607,27 @@ struct topa { static struct topa *topa_alloc(int cpu, gfp_t gfp) { int node = cpu_to_node(cpu); - struct topa *topa; + struct topa_page *tp; struct page *p; p = alloc_pages_node(node, gfp | __GFP_ZERO, 0); if (!p) return NULL; - topa = page_address(p); - topa->last = 0; - topa->phys = page_to_phys(p); + tp = page_address(p); + tp->topa.last = 0; + tp->topa.phys = page_to_phys(p); /* * In case of singe-entry ToPA, always put the self-referencing END * link as the 2nd entry in the table */ if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) { - TOPA_ENTRY(topa, 1)->base = topa->phys >> TOPA_SHIFT; - TOPA_ENTRY(topa, 1)->end = 1; + TOPA_ENTRY(&tp->topa, 1)->base = tp->topa.phys; + TOPA_ENTRY(&tp->topa, 1)->end = 1; } - return topa; + return &tp->topa; } /** @@ -715,22 +737,23 @@ static void pt_topa_dump(struct pt_buffer *buf) struct topa *topa; list_for_each_entry(topa, &buf->tables, list) { + struct topa_page *tp = topa_to_page(topa); int i; - pr_debug("# table @%p (%016Lx), off %llx size %zx\n", topa->table, + pr_debug("# table @%p (%016Lx), off %llx size %zx\n", tp->table, topa->phys, topa->offset, topa->size); for (i = 0; i < TENTS_PER_PAGE; i++) { pr_debug("# entry @%p (%lx sz %u %c%c%c) raw=%16llx\n", - &topa->table[i], - (unsigned long)topa->table[i].base << TOPA_SHIFT, - sizes(topa->table[i].size), - topa->table[i].end ? 'E' : ' ', - topa->table[i].intr ? 'I' : ' ', - topa->table[i].stop ? 'S' : ' ', - *(u64 *)&topa->table[i]); + &tp->table[i], + (unsigned long)tp->table[i].base << TOPA_SHIFT, + sizes(tp->table[i].size), + tp->table[i].end ? 'E' : ' ', + tp->table[i].intr ? 'I' : ' ', + tp->table[i].stop ? 'S' : ' ', + *(u64 *)&tp->table[i]); if ((intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries) && - topa->table[i].stop) || - topa->table[i].end) + tp->table[i].stop) || + tp->table[i].end) break; } } @@ -793,7 +816,7 @@ static void pt_update_head(struct pt *pt) */ static void *pt_buffer_region(struct pt_buffer *buf) { - return phys_to_virt(buf->cur->table[buf->cur_idx].base << TOPA_SHIFT); + return phys_to_virt(TOPA_ENTRY(buf->cur, buf->cur_idx)->base << TOPA_SHIFT); } /** @@ -870,9 +893,11 @@ static void pt_handle_status(struct pt *pt) static void pt_read_offset(struct pt_buffer *buf) { u64 offset, base_topa; + struct topa_page *tp; rdmsrl(MSR_IA32_RTIT_OUTPUT_BASE, base_topa); - buf->cur = phys_to_virt(base_topa); + tp = phys_to_virt(base_topa); + buf->cur = &tp->topa; rdmsrl(MSR_IA32_RTIT_OUTPUT_MASK, offset); /* offset within current output region */ @@ -1022,6 +1047,7 @@ static void pt_buffer_setup_topa_index(struct pt_buffer *buf) */ static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head) { + struct topa_page *cur_tp; int pg; if (buf->snapshot) @@ -1030,7 +1056,8 @@ static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head) pg = (head >> PAGE_SHIFT) & (buf->nr_pages - 1); pg = pt_topa_next_entry(buf, pg); - buf->cur = (struct topa *)((unsigned long)buf->topa_index[pg] & PAGE_MASK); + cur_tp = topa_entry_to_page(buf->topa_index[pg]); + buf->cur = &cur_tp->topa; buf->cur_idx = buf->topa_index[pg] - TOPA_ENTRY(buf->cur, 0); buf->output_off = head & (pt_buffer_region_size(buf) - 1); @@ -1296,7 +1323,7 @@ void intel_pt_interrupt(void) return; } - pt_config_buffer(buf->cur->table, buf->cur_idx, + pt_config_buffer(topa_to_page(buf->cur)->table, buf->cur_idx, buf->output_off); pt_config(event); } @@ -1361,7 +1388,7 @@ static void pt_event_start(struct perf_event *event, int mode) WRITE_ONCE(pt->handle_nmi, 1); hwc->state = 0; - pt_config_buffer(buf->cur->table, buf->cur_idx, + pt_config_buffer(topa_to_page(buf->cur)->table, buf->cur_idx, buf->output_off); pt_config(event); -- 2.43.0
