diff options
| author | Tiwei Bie <tiwei.btw@antgroup.com> | 2025-10-27 08:18:12 +0800 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2025-10-27 16:41:15 +0100 |
| commit | 1e4ee5135d814fe4785890790cec81c3132888fb (patch) | |
| tree | b88d4e37829af3c801081a25d2a08ce23600f59c /arch/um/kernel/um_arch.c | |
| parent | 9c82de55d4783e906f18219f833ad97fd8d9c5df (diff) | |
um: Add initial SMP support
Add initial symmetric multi-processing (SMP) support to UML. With
this support enabled, users can tell UML to start multiple virtual
processors, each represented as a separate host thread.
In UML, kthreads and normal threads (when running in kernel mode)
can be scheduled and executed simultaneously on different virtual
processors. However, the userspace code of normal threads still
runs within their respective single-threaded stubs.
That is, SMP support is currently available both within the kernel
and across different processes, but still remains limited within
threads of the same process in userspace.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20251027001815.1666872-6-tiwei.bie@linux.dev
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'arch/um/kernel/um_arch.c')
| -rw-r--r-- | arch/um/kernel/um_arch.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index cf06bb732ed8..e2b24e1ecfa6 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -19,6 +19,7 @@ #include <linux/kmsg_dump.h> #include <linux/suspend.h> #include <linux/random.h> +#include <linux/smp-internal.h> #include <asm/processor.h> #include <asm/cpufeature.h> @@ -71,6 +72,12 @@ static int show_cpuinfo(struct seq_file *m, void *v) { int i = 0; +#if IS_ENABLED(CONFIG_SMP) + i = (uintptr_t) v - 1; + if (!cpu_online(i)) + return 0; +#endif + seq_printf(m, "processor\t: %d\n", i); seq_printf(m, "vendor_id\t: User Mode Linux\n"); seq_printf(m, "model name\t: UML\n"); @@ -87,13 +94,14 @@ static int show_cpuinfo(struct seq_file *m, void *v) loops_per_jiffy/(500000/HZ), (loops_per_jiffy/(5000/HZ)) % 100); - return 0; } static void *c_start(struct seq_file *m, loff_t *pos) { - return *pos < nr_cpu_ids ? &boot_cpu_data + *pos : NULL; + if (*pos < nr_cpu_ids) + return (void *)(uintptr_t)(*pos + 1); + return NULL; } static void *c_next(struct seq_file *m, void *v, loff_t *pos) @@ -409,6 +417,7 @@ void __init setup_arch(char **cmdline_p) strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE); *cmdline_p = command_line; setup_hostinfo(host_info, sizeof host_info); + prefill_possible_map(); if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) { add_bootloader_randomness(rng_seed, sizeof(rng_seed)); @@ -443,6 +452,18 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end) { } +#if IS_ENABLED(CONFIG_SMP) +void alternatives_smp_module_add(struct module *mod, char *name, + void *locks, void *locks_end, + void *text, void *text_end) +{ +} + +void alternatives_smp_module_del(struct module *mod) +{ +} +#endif + void *text_poke(void *addr, const void *opcode, size_t len) { /* |