Merge tag 'x86_bugs_for_v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 spectre fixes from Borislav Petkov:

 - Mitigate Spectre v2-type Branch History Buffer attacks on machines
   which support eIBRS, i.e., the hardware-assisted speculation
   restriction after it has been shown that such machines are vulnerable
   even with the hardware mitigation.

 - Do not use the default LFENCE-based Spectre v2 mitigation on AMD as
   it is insufficient to mitigate such attacks. Instead, switch to
   retpolines on all AMD by default.

 - Update the docs and add some warnings for the obviously vulnerable
   cmdline configurations.

* tag 'x86_bugs_for_v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
  x86/speculation: Warn about Spectre v2 LFENCE mitigation
  x86/speculation: Update link to AMD speculation whitepaper
  x86/speculation: Use generic retpoline by default on AMD
  x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
  Documentation/hw-vuln: Update spectre doc
  x86/speculation: Add eIBRS + Retpoline options
  x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d0ad379d1e62..3121d1fc8e75 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1792,6 +1792,11 @@ struct bpf_core_ctx {
 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
 		   int relo_idx, void *insn);
 
+static inline bool unprivileged_ebpf_enabled(void)
+{
+	return !sysctl_unprivileged_bpf_disabled;
+}
+
 #else /* !CONFIG_BPF_SYSCALL */
 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 {
@@ -2011,6 +2016,12 @@ bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
 {
 	return NULL;
 }
+
+static inline bool unprivileged_ebpf_enabled(void)
+{
+	return false;
+}
+
 #endif /* CONFIG_BPF_SYSCALL */
 
 void __bpf_free_used_btfs(struct bpf_prog_aux *aux,