diff options
Diffstat (limited to 'arch/powerpc/kernel/security.c')
| -rw-r--r-- | arch/powerpc/kernel/security.c | 263 |
1 files changed, 262 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c index e4e1a94ccf6a..0fdfcdd9d880 100644 --- a/arch/powerpc/kernel/security.c +++ b/arch/powerpc/kernel/security.c @@ -7,6 +7,7 @@ #include <linux/cpu.h> #include <linux/kernel.h> #include <linux/device.h> +#include <linux/memblock.h> #include <linux/nospec.h> #include <linux/prctl.h> #include <linux/seq_buf.h> @@ -18,6 +19,7 @@ #include <asm/setup.h> #include <asm/inst.h> +#include "setup.h" u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT; @@ -250,7 +252,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c static enum stf_barrier_type stf_enabled_flush_types; static bool no_stf_barrier; -bool stf_barrier; +static bool stf_barrier; static int __init handle_no_stf_barrier(char *p) { @@ -541,6 +543,178 @@ void setup_count_cache_flush(void) toggle_branch_cache_flush(enable); } +static enum l1d_flush_type enabled_flush_types; +static void *l1d_flush_fallback_area; +static bool no_rfi_flush; +static bool no_entry_flush; +static bool no_uaccess_flush; +bool rfi_flush; +static bool entry_flush; +static bool uaccess_flush; +DEFINE_STATIC_KEY_FALSE(uaccess_flush_key); +EXPORT_SYMBOL(uaccess_flush_key); + +static int __init handle_no_rfi_flush(char *p) +{ + pr_info("rfi-flush: disabled on command line."); + no_rfi_flush = true; + return 0; +} +early_param("no_rfi_flush", handle_no_rfi_flush); + +static int __init handle_no_entry_flush(char *p) +{ + pr_info("entry-flush: disabled on command line."); + no_entry_flush = true; + return 0; +} +early_param("no_entry_flush", handle_no_entry_flush); + +static int __init handle_no_uaccess_flush(char *p) +{ + pr_info("uaccess-flush: disabled on command line."); + no_uaccess_flush = true; + return 0; +} +early_param("no_uaccess_flush", handle_no_uaccess_flush); + +/* + * The RFI flush is not KPTI, but because users will see doco that says to use + * nopti we hijack that option here to also disable the RFI flush. + */ +static int __init handle_no_pti(char *p) +{ + pr_info("rfi-flush: disabling due to 'nopti' on command line.\n"); + handle_no_rfi_flush(NULL); + return 0; +} +early_param("nopti", handle_no_pti); + +static void do_nothing(void *unused) +{ + /* + * We don't need to do the flush explicitly, just enter+exit kernel is + * sufficient, the RFI exit handlers will do the right thing. + */ +} + +void rfi_flush_enable(bool enable) +{ + if (enable) { + do_rfi_flush_fixups(enabled_flush_types); + on_each_cpu(do_nothing, NULL, 1); + } else + do_rfi_flush_fixups(L1D_FLUSH_NONE); + + rfi_flush = enable; +} + +static void entry_flush_enable(bool enable) +{ + if (enable) { + do_entry_flush_fixups(enabled_flush_types); + on_each_cpu(do_nothing, NULL, 1); + } else { + do_entry_flush_fixups(L1D_FLUSH_NONE); + } + + entry_flush = enable; +} + +static void uaccess_flush_enable(bool enable) +{ + if (enable) { + do_uaccess_flush_fixups(enabled_flush_types); + static_branch_enable(&uaccess_flush_key); + on_each_cpu(do_nothing, NULL, 1); + } else { + static_branch_disable(&uaccess_flush_key); + do_uaccess_flush_fixups(L1D_FLUSH_NONE); + } + + uaccess_flush = enable; +} + +static void __ref init_fallback_flush(void) +{ + u64 l1d_size, limit; + int cpu; + + /* Only allocate the fallback flush area once (at boot time). */ + if (l1d_flush_fallback_area) + return; + + l1d_size = ppc64_caches.l1d.size; + + /* + * If there is no d-cache-size property in the device tree, l1d_size + * could be zero. That leads to the loop in the asm wrapping around to + * 2^64-1, and then walking off the end of the fallback area and + * eventually causing a page fault which is fatal. Just default to + * something vaguely sane. + */ + if (!l1d_size) + l1d_size = (64 * 1024); + + limit = min(ppc64_bolted_size(), ppc64_rma_size); + + /* + * Align to L1d size, and size it at 2x L1d size, to catch possible + * hardware prefetch runoff. We don't have a recipe for load patterns to + * reliably avoid the prefetcher. + */ + l1d_flush_fallback_area = memblock_alloc_try_nid(l1d_size * 2, + l1d_size, MEMBLOCK_LOW_LIMIT, + limit, NUMA_NO_NODE); + if (!l1d_flush_fallback_area) + panic("%s: Failed to allocate %llu bytes align=0x%llx max_addr=%pa\n", + __func__, l1d_size * 2, l1d_size, &limit); + + + for_each_possible_cpu(cpu) { + struct paca_struct *paca = paca_ptrs[cpu]; + paca->rfi_flush_fallback_area = l1d_flush_fallback_area; + paca->l1d_flush_size = l1d_size; + } +} + +void setup_rfi_flush(enum l1d_flush_type types, bool enable) +{ + if (types & L1D_FLUSH_FALLBACK) { + pr_info("rfi-flush: fallback displacement flush available\n"); + init_fallback_flush(); + } + + if (types & L1D_FLUSH_ORI) + pr_info("rfi-flush: ori type flush available\n"); + + if (types & L1D_FLUSH_MTTRIG) + pr_info("rfi-flush: mttrig type flush available\n"); + + enabled_flush_types = types; + + if (!cpu_mitigations_off() && !no_rfi_flush) + rfi_flush_enable(enable); +} + +void setup_entry_flush(bool enable) +{ + if (cpu_mitigations_off()) + return; + + if (!no_entry_flush) + entry_flush_enable(enable); +} + +void setup_uaccess_flush(bool enable) +{ + if (cpu_mitigations_off()) + return; + + if (!no_uaccess_flush) + uaccess_flush_enable(enable); +} + #ifdef CONFIG_DEBUG_FS static int count_cache_flush_set(void *data, u64 val) { @@ -579,5 +753,92 @@ static __init int count_cache_flush_debugfs_init(void) return 0; } device_initcall(count_cache_flush_debugfs_init); + +static int rfi_flush_set(void *data, u64 val) +{ + bool enable; + + if (val == 1) + enable = true; + else if (val == 0) + enable = false; + else + return -EINVAL; + + /* Only do anything if we're changing state */ + if (enable != rfi_flush) + rfi_flush_enable(enable); + + return 0; +} + +static int rfi_flush_get(void *data, u64 *val) +{ + *val = rfi_flush ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n"); + +static int entry_flush_set(void *data, u64 val) +{ + bool enable; + + if (val == 1) + enable = true; + else if (val == 0) + enable = false; + else + return -EINVAL; + + /* Only do anything if we're changing state */ + if (enable != entry_flush) + entry_flush_enable(enable); + + return 0; +} + +static int entry_flush_get(void *data, u64 *val) +{ + *val = entry_flush ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_entry_flush, entry_flush_get, entry_flush_set, "%llu\n"); + +static int uaccess_flush_set(void *data, u64 val) +{ + bool enable; + + if (val == 1) + enable = true; + else if (val == 0) + enable = false; + else + return -EINVAL; + + /* Only do anything if we're changing state */ + if (enable != uaccess_flush) + uaccess_flush_enable(enable); + + return 0; +} + +static int uaccess_flush_get(void *data, u64 *val) +{ + *val = uaccess_flush ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_uaccess_flush, uaccess_flush_get, uaccess_flush_set, "%llu\n"); + +static __init int rfi_flush_debugfs_init(void) +{ + debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush); + debugfs_create_file("entry_flush", 0600, powerpc_debugfs_root, NULL, &fops_entry_flush); + debugfs_create_file("uaccess_flush", 0600, powerpc_debugfs_root, NULL, &fops_uaccess_flush); + return 0; +} +device_initcall(rfi_flush_debugfs_init); #endif /* CONFIG_DEBUG_FS */ #endif /* CONFIG_PPC_BOOK3S_64 */ |