Merge tag 'kvmarm-fixes-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.12, take #1

- Fix pKVM error path on init, making sure we do not change critical
  system registers as we're about to fail

- Make sure that the host's vector length is at capped by a value
  common to all CPUs

- Fix kvm_has_feat*() handling of "negative" features, as the current
  code is pretty broken

- Promote Joey to the status of official reviewer, while James steps
  down -- hopefully only temporarly

4 files changed, 84 insertions, 5 deletions

diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index aee479d2191c..69b66994f2a1 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -122,7 +122,7 @@ static bool decode_insn_reg2i12_fomat(union loongarch_instruction inst,
 	switch (inst.reg2i12_format.opcode) {
 	case addid_op:
 		if ((inst.reg2i12_format.rd == CFI_SP) || (inst.reg2i12_format.rj == CFI_SP)) {
-			/* addi.d sp,sp,si12 or addi.d fp,sp,si12 */
+			/* addi.d sp,sp,si12 or addi.d fp,sp,si12 or addi.d sp,fp,si12 */
 			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
 			ADD_OP(op) {
 				op->src.type = OP_SRC_ADD;
@@ -132,6 +132,15 @@ static bool decode_insn_reg2i12_fomat(union loongarch_instruction inst,
 				op->dest.reg = inst.reg2i12_format.rd;
 			}
 		}
+		if ((inst.reg2i12_format.rd == CFI_SP) && (inst.reg2i12_format.rj == CFI_FP)) {
+			/* addi.d sp,fp,si12 */
+			struct symbol *func = find_func_containing(insn->sec, insn->offset);
+
+			if (!func)
+				return false;
+
+			func->frame_pointer = true;
+		}
 		break;
 	case ldd_op:
 		if (inst.reg2i12_format.rj == CFI_SP) {
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 01237d167223..6604f5d038aa 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -178,6 +178,52 @@ static bool is_sibling_call(struct instruction *insn)
 }
 
 /*
+ * Checks if a string ends with another.
+ */
+static bool str_ends_with(const char *s, const char *sub)
+{
+	const int slen = strlen(s);
+	const int sublen = strlen(sub);
+
+	if (sublen > slen)
+		return 0;
+
+	return !memcmp(s + slen - sublen, sub, sublen);
+}
+
+/*
+ * Checks if a function is a Rust "noreturn" one.
+ */
+static bool is_rust_noreturn(const struct symbol *func)
+{
+	/*
+	 * If it does not start with "_R", then it is not a Rust symbol.
+	 */
+	if (strncmp(func->name, "_R", 2))
+		return false;
+
+	/*
+	 * These are just heuristics -- we do not control the precise symbol
+	 * name, due to the crate disambiguators (which depend on the compiler)
+	 * as well as changes to the source code itself between versions (since
+	 * these come from the Rust standard library).
+	 */
+	return str_ends_with(func->name, "_4core5sliceSp15copy_from_slice17len_mismatch_fail")		||
+	       str_ends_with(func->name, "_4core6option13unwrap_failed")				||
+	       str_ends_with(func->name, "_4core6result13unwrap_failed")				||
+	       str_ends_with(func->name, "_4core9panicking5panic")					||
+	       str_ends_with(func->name, "_4core9panicking9panic_fmt")					||
+	       str_ends_with(func->name, "_4core9panicking14panic_explicit")				||
+	       str_ends_with(func->name, "_4core9panicking14panic_nounwind")				||
+	       str_ends_with(func->name, "_4core9panicking18panic_bounds_check")			||
+	       str_ends_with(func->name, "_4core9panicking19assert_failed_inner")			||
+	       str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference")	||
+	       strstr(func->name, "_4core9panicking11panic_const24panic_const_")			||
+	       (strstr(func->name, "_4core5slice5index24slice_") &&
+		str_ends_with(func->name, "_fail"));
+}
+
+/*
  * This checks to see if the given function is a "noreturn" function.
  *
  * For global functions which are outside the scope of this object file, we
@@ -202,10 +248,14 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 	if (!func)
 		return false;
 
-	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK)
+	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) {
+		if (is_rust_noreturn(func))
+			return true;
+
 		for (i = 0; i < ARRAY_SIZE(global_noreturns); i++)
 			if (!strcmp(func->name, global_noreturns[i]))
 				return true;
+	}
 
 	if (func->bind == STB_WEAK)
 		return false;
@@ -2993,10 +3043,27 @@ static int update_cfi_state(struct instruction *insn,
 				break;
 			}
 
-			if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
+			if (op->dest.reg == CFI_BP && op->src.reg == CFI_SP &&
+			    insn->sym->frame_pointer) {
+				/* addi.d fp,sp,imm on LoongArch */
+				if (cfa->base == CFI_SP && cfa->offset == op->src.offset) {
+					cfa->base = CFI_BP;
+					cfa->offset = 0;
+				}
+				break;
+			}
 
-				/* lea disp(%rbp), %rsp */
-				cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset);
+			if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
+				/* addi.d sp,fp,imm on LoongArch */
+				if (cfa->base == CFI_BP && cfa->offset == 0) {
+					if (insn->sym->frame_pointer) {
+						cfa->base = CFI_SP;
+						cfa->offset = -op->src.offset;
+					}
+				} else {
+					/* lea disp(%rbp), %rsp */
+					cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset);
+				}
 				break;
 			}
 
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 2b8a69de4db8..d7e815c2fd15 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -68,6 +68,7 @@ struct symbol {
 	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
 	u8 local_label       : 1;
+	u8 frame_pointer     : 1;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };
diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h
index 1e8141ef1b15..e7da92489167 100644
--- a/tools/objtool/noreturns.h
+++ b/tools/objtool/noreturns.h
@@ -39,6 +39,8 @@ NORETURN(panic)
 NORETURN(panic_smp_self_stop)
 NORETURN(rest_init)
 NORETURN(rewind_stack_and_make_dead)
+NORETURN(rust_begin_unwind)
+NORETURN(rust_helper_BUG)
 NORETURN(sev_es_terminate)
 NORETURN(snp_abort)
 NORETURN(start_kernel)