[PATCH v5 1/3] x86/mce/mce-inject: Replace struct i_mce with struct inject_desc

[Smita Koralahalli]

Replace the existing struct i_mce with struct inject_desc. Extend the
struct to include "error" field. This error field will be useful to
return error codes to userspace when error injection fails.

Suggested-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
Link: https://lkml.kernel.org/r/Yk267A1MKOo2AlXQ@xxxxxxx
---
 arch/x86/kernel/cpu/mce/inject.c | 94 ++++++++++++++++++--------------
 1 file changed, 52 insertions(+), 42 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index 5fbd7ffb3233..05581b718529 100644
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -33,10 +33,12 @@
 
 #include "internal.h"
 
-/*
- * Collect all the MCi_XXX settings
- */
-static struct mce i_mce;
+/* Collect all the MCi_XXX settings */
+static struct inject_desc {
+	struct mce m;
+	int err;
+} inj_desc;
+
 static struct dentry *dfs_inj;
 
 #define MAX_FLAG_OPT_SIZE	4
@@ -110,9 +112,11 @@ static int inj_ipid_set(void *data, u64 val)
 
 DEFINE_SIMPLE_ATTRIBUTE(ipid_fops, inj_ipid_get, inj_ipid_set, "%llx\n");
 
-static void setup_inj_struct(struct mce *m)
+static void setup_inj_struct(void)
 {
-	memset(m, 0, sizeof(struct mce));
+	struct mce *m = &inj_desc.m;
+
+	memset(&inj_desc, 0, sizeof(struct inject_desc));
 
 	m->cpuvendor = boot_cpu_data.x86_vendor;
 	m->time	     = ktime_get_real_seconds();
@@ -470,56 +474,57 @@ static void toggle_nb_mca_mst_cpu(u16 nid)
 		       __func__, PCI_FUNC(F3->devfn), NBCFG);
 }
 
-static void prepare_msrs(void *info)
+static void prepare_msrs(void *unused)
 {
-	struct mce m = *(struct mce *)info;
-	u8 b = m.bank;
+	struct mce *m = &inj_desc.m;
+	u8 b = inj_desc.m.bank;
 
-	wrmsrl(MSR_IA32_MCG_STATUS, m.mcgstatus);
+	wrmsrl(MSR_IA32_MCG_STATUS, m->mcgstatus);
 
 	if (boot_cpu_has(X86_FEATURE_SMCA)) {
-		if (m.inject_flags == DFR_INT_INJ) {
-			wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(b), m.status);
-			wrmsrl(MSR_AMD64_SMCA_MCx_DEADDR(b), m.addr);
+		if (m->inject_flags == DFR_INT_INJ) {
+			wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(b), m->status);
+			wrmsrl(MSR_AMD64_SMCA_MCx_DEADDR(b), m->addr);
 		} else {
-			wrmsrl(MSR_AMD64_SMCA_MCx_STATUS(b), m.status);
-			wrmsrl(MSR_AMD64_SMCA_MCx_ADDR(b), m.addr);
+			wrmsrl(MSR_AMD64_SMCA_MCx_STATUS(b), m->status);
+			wrmsrl(MSR_AMD64_SMCA_MCx_ADDR(b), m->addr);
 		}
 
-		wrmsrl(MSR_AMD64_SMCA_MCx_MISC(b), m.misc);
-		wrmsrl(MSR_AMD64_SMCA_MCx_SYND(b), m.synd);
+		wrmsrl(MSR_AMD64_SMCA_MCx_MISC(b), m->misc);
+		wrmsrl(MSR_AMD64_SMCA_MCx_SYND(b), m->synd);
 	} else {
-		wrmsrl(MSR_IA32_MCx_STATUS(b), m.status);
-		wrmsrl(MSR_IA32_MCx_ADDR(b), m.addr);
-		wrmsrl(MSR_IA32_MCx_MISC(b), m.misc);
+		wrmsrl(MSR_IA32_MCx_STATUS(b), m->status);
+		wrmsrl(MSR_IA32_MCx_ADDR(b), m->addr);
+		wrmsrl(MSR_IA32_MCx_MISC(b), m->misc);
 	}
 }
 
-static void do_inject(void)
+static int do_inject(void)
 {
+	struct mce *m = &inj_desc.m;
+	unsigned int cpu = m->extcpu;
 	u64 mcg_status = 0;
-	unsigned int cpu = i_mce.extcpu;
-	u8 b = i_mce.bank;
+	u8 b = m->bank;
 
-	i_mce.tsc = rdtsc_ordered();
+	m->tsc = rdtsc_ordered();
 
-	i_mce.status |= MCI_STATUS_VAL;
+	m->status |= MCI_STATUS_VAL;
 
-	if (i_mce.misc)
-		i_mce.status |= MCI_STATUS_MISCV;
+	if (m->misc)
+		m->status |= MCI_STATUS_MISCV;
 
-	if (i_mce.synd)
-		i_mce.status |= MCI_STATUS_SYNDV;
+	if (m->synd)
+		m->status |= MCI_STATUS_SYNDV;
 
 	if (inj_type == SW_INJ) {
-		mce_log(&i_mce);
-		return;
+		mce_log(m);
+		return 0;
 	}
 
 	/* prep MCE global settings for the injection */
 	mcg_status = MCG_STATUS_MCIP | MCG_STATUS_EIPV;
 
-	if (!(i_mce.status & MCI_STATUS_PCC))
+	if (!(m->status & MCI_STATUS_PCC))
 		mcg_status |= MCG_STATUS_RIPV;
 
 	/*
@@ -528,8 +533,8 @@ static void do_inject(void)
 	 * - MCx_STATUS[UC] cleared: deferred errors are _not_ UC
 	 */
 	if (inj_type == DFR_INT_INJ) {
-		i_mce.status |= MCI_STATUS_DEFERRED;
-		i_mce.status &= ~MCI_STATUS_UC;
+		m->status |= MCI_STATUS_DEFERRED;
+		m->status &= ~MCI_STATUS_UC;
 	}
 
 	/*
@@ -550,12 +555,15 @@ static void do_inject(void)
 
 	toggle_hw_mce_inject(cpu, true);
 
-	i_mce.mcgstatus = mcg_status;
-	i_mce.inject_flags = inj_type;
-	smp_call_function_single(cpu, prepare_msrs, &i_mce, 0);
+	m->mcgstatus = mcg_status;
+	m->inject_flags = inj_type;
+	smp_call_function_single(cpu, prepare_msrs, NULL, 0);
 
 	toggle_hw_mce_inject(cpu, false);
 
+	if (inj_desc.err)
+		goto err;
+
 	switch (inj_type) {
 	case DFR_INT_INJ:
 		smp_call_function_single(cpu, trigger_dfr_int, NULL, 0);
@@ -570,6 +578,7 @@ static void do_inject(void)
 err:
 	cpus_read_unlock();
 
+	return inj_desc.err;
 }
 
 /*
@@ -580,6 +589,7 @@ static int inj_bank_set(void *data, u64 val)
 {
 	struct mce *m = (struct mce *)data;
 	u8 n_banks;
+	int err;
 	u64 cap;
 
 	/* Get bank count on target CPU so we can handle non-uniform values. */
@@ -619,12 +629,12 @@ static int inj_bank_set(void *data, u64 val)
 	}
 
 inject:
-	do_inject();
+	err = do_inject();
 
 	/* Reset injection struct */
-	setup_inj_struct(&i_mce);
+	setup_inj_struct();
 
-	return 0;
+	return err;
 }
 
 MCE_INJECT_GET(bank);
@@ -714,7 +724,7 @@ static void __init debugfs_init(void)
 
 	for (i = 0; i < ARRAY_SIZE(dfs_fls); i++)
 		debugfs_create_file(dfs_fls[i].name, dfs_fls[i].perm, dfs_inj,
-				    &i_mce, dfs_fls[i].fops);
+				    &inj_desc.m, dfs_fls[i].fops);
 }
 
 static int __init inject_init(void)
@@ -727,7 +737,7 @@ static int __init inject_init(void)
 	register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
 	mce_register_injector_chain(&inject_nb);
 
-	setup_inj_struct(&i_mce);
+	setup_inj_struct();
 
 	pr_info("Machine check injector initialized\n");
 
-- 
2.17.1