ACPI / APEI: Let the notification helper specify the fixmap slot

ghes_copy_tofrom_phys() uses a different fixmap slot depending on in_nmi().
This doesn't work when there are multiple NMI-like notifications, that
could interrupt each other.

As with the locking, move the chosen fixmap_idx to the notification helper.
This only matters for NMI-like notifications, anything calling
ghes_proc() can use the IRQ fixmap slot as its already holding an irqsave
spinlock.

This lets us collapse the ghes_ioremap_pfn_*() helpers.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index c7dbdb915e7e14213d1ff4fd48bcc608720672c3..9a24641adfba1f97c0c0673303281f4d65f855e4 100644 (file)
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -41,6 +41,7 @@
 #include <linux/llist.h>
 #include <linux/genalloc.h>
 #include <linux/pci.h>
+#include <linux/pfn.h>
 #include <linux/aer.h>
 #include <linux/nmi.h>
 #include <linux/sched/clock.h>
@@ -127,38 +128,24 @@ static atomic_t ghes_estatus_cache_alloced;
 
 static int ghes_panic_timeout __read_mostly = 30;
 
-static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
+static void __iomem *ghes_map(u64 pfn, enum fixed_addresses fixmap_idx)
 {
        phys_addr_t paddr;
        pgprot_t prot;
 
-       paddr = pfn << PAGE_SHIFT;
+       paddr = PFN_PHYS(pfn);
        prot = arch_apei_get_mem_attribute(paddr);
-       __set_fixmap(FIX_APEI_GHES_NMI, paddr, prot);
+       __set_fixmap(fixmap_idx, paddr, prot);
 
-       return (void __iomem *) fix_to_virt(FIX_APEI_GHES_NMI);
+       return (void __iomem *) __fix_to_virt(fixmap_idx);
 }
 
-static void __iomem *ghes_ioremap_pfn_irq(u64 pfn)
+static void ghes_unmap(void __iomem *vaddr, enum fixed_addresses fixmap_idx)
 {
-       phys_addr_t paddr;
-       pgprot_t prot;
-
-       paddr = pfn << PAGE_SHIFT;
-       prot = arch_apei_get_mem_attribute(paddr);
-       __set_fixmap(FIX_APEI_GHES_IRQ, paddr, prot);
+       int _idx = virt_to_fix((unsigned long)vaddr);
 
-       return (void __iomem *) fix_to_virt(FIX_APEI_GHES_IRQ);
-}
-
-static void ghes_iounmap_nmi(void)
-{
-       clear_fixmap(FIX_APEI_GHES_NMI);
-}
-
-static void ghes_iounmap_irq(void)
-{
-       clear_fixmap(FIX_APEI_GHES_IRQ);
+       WARN_ON_ONCE(fixmap_idx != _idx);
+       clear_fixmap(fixmap_idx);
 }
 
 int ghes_estatus_pool_init(int num_ghes)
@@ -283,20 +270,16 @@ static inline int ghes_severity(int severity)
 }
 
 static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
-                                 int from_phys)
+                                 int from_phys,
+                                 enum fixed_addresses fixmap_idx)
 {
        void __iomem *vaddr;
-       int in_nmi = in_nmi();
        u64 offset;
        u32 trunk;
 
        while (len > 0) {
                offset = paddr - (paddr & PAGE_MASK);
-               if (in_nmi) {
-                       vaddr = ghes_ioremap_pfn_nmi(paddr >> PAGE_SHIFT);
-               } else {
-                       vaddr = ghes_ioremap_pfn_irq(paddr >> PAGE_SHIFT);
-               }
+               vaddr = ghes_map(PHYS_PFN(paddr), fixmap_idx);
                trunk = PAGE_SIZE - offset;
                trunk = min(trunk, len);
                if (from_phys)
@@ -306,15 +289,13 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
                len -= trunk;
                paddr += trunk;
                buffer += trunk;
-               if (in_nmi) {
-                       ghes_iounmap_nmi();
-               } else {
-                       ghes_iounmap_irq();
-               }
+               ghes_unmap(vaddr, fixmap_idx);
        }
 }
 
-static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr)
+static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr,
+                            enum fixed_addresses fixmap_idx)
+
 {
        struct acpi_hest_generic *g = ghes->generic;
        u32 len;
@@ -332,7 +313,7 @@ static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr)
                return -ENOENT;
 
        ghes_copy_tofrom_phys(ghes->estatus, *buf_paddr,
-                             sizeof(*ghes->estatus), 1);
+                             sizeof(*ghes->estatus), 1, fixmap_idx);
        if (!ghes->estatus->block_status) {
                *buf_paddr = 0;
                return -ENOENT;
@@ -348,7 +329,7 @@ static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr)
                goto err_read_block;
        ghes_copy_tofrom_phys(ghes->estatus + 1,
                              *buf_paddr + sizeof(*ghes->estatus),
-                             len - sizeof(*ghes->estatus), 1);
+                             len - sizeof(*ghes->estatus), 1, fixmap_idx);
        if (cper_estatus_check(ghes->estatus))
                goto err_read_block;
        rc = 0;
@@ -361,7 +342,8 @@ err_read_block:
        return rc;
 }
 
-static void ghes_clear_estatus(struct ghes *ghes, u64 buf_paddr)
+static void ghes_clear_estatus(struct ghes *ghes, u64 buf_paddr,
+                              enum fixed_addresses fixmap_idx)
 {
        ghes->estatus->block_status = 0;
 
@@ -369,7 +351,8 @@ static void ghes_clear_estatus(struct ghes *ghes, u64 buf_paddr)
                return;
 
        ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
-                             sizeof(ghes->estatus->block_status), 0);
+                             sizeof(ghes->estatus->block_status), 0,
+                             fixmap_idx);
 
        /*
         * GHESv2 type HEST entries introduce support for error acknowledgment,
@@ -668,11 +651,12 @@ static void ghes_estatus_cache_add(
        rcu_read_unlock();
 }
 
-static void __ghes_panic(struct ghes *ghes, u64 buf_paddr)
+static void __ghes_panic(struct ghes *ghes, u64 buf_paddr,
+                        enum fixed_addresses fixmap_idx)
 {
        __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
 
-       ghes_clear_estatus(ghes, buf_paddr);
+       ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
 
        /* reboot to log the error! */
        if (!panic_timeout)
@@ -685,12 +669,12 @@ static int ghes_proc(struct ghes *ghes)
        u64 buf_paddr;
        int rc;
 
-       rc = ghes_read_estatus(ghes, &buf_paddr);
+       rc = ghes_read_estatus(ghes, &buf_paddr, FIX_APEI_GHES_IRQ);
        if (rc)
                goto out;
 
        if (ghes_severity(ghes->estatus->error_severity) >= GHES_SEV_PANIC) {
-               __ghes_panic(ghes, buf_paddr);
+               __ghes_panic(ghes, buf_paddr, FIX_APEI_GHES_IRQ);
        }
 
        if (!ghes_estatus_cached(ghes->estatus)) {
@@ -700,7 +684,7 @@ static int ghes_proc(struct ghes *ghes)
        ghes_do_proc(ghes, ghes->estatus);
 
 out:
-       ghes_clear_estatus(ghes, buf_paddr);
+       ghes_clear_estatus(ghes, buf_paddr, FIX_APEI_GHES_IRQ);
 
        return rc;
 }
@@ -866,36 +850,38 @@ static void __process_error(struct ghes *ghes)
 #endif
 }
 
-static int ghes_in_nmi_queue_one_entry(struct ghes *ghes)
+static int ghes_in_nmi_queue_one_entry(struct ghes *ghes,
+                                      enum fixed_addresses fixmap_idx)
 {
        u64 buf_paddr;
        int sev;
 
-       if (ghes_read_estatus(ghes, &buf_paddr)) {
-               ghes_clear_estatus(ghes, buf_paddr);
+       if (ghes_read_estatus(ghes, &buf_paddr, fixmap_idx)) {
+               ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
                return -ENOENT;
        }
 
        sev = ghes_severity(ghes->estatus->error_severity);
        if (sev >= GHES_SEV_PANIC) {
                ghes_print_queued_estatus();
-               __ghes_panic(ghes, buf_paddr);
+               __ghes_panic(ghes, buf_paddr, fixmap_idx);
        }
 
        __process_error(ghes);
-       ghes_clear_estatus(ghes, buf_paddr);
+       ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
 
        return 0;
 }
 
-static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list)
+static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list,
+                                      enum fixed_addresses fixmap_idx)
 {
        int ret = -ENOENT;
        struct ghes *ghes;
 
        rcu_read_lock();
        list_for_each_entry_rcu(ghes, rcu_list, list) {
-               if (!ghes_in_nmi_queue_one_entry(ghes))
+               if (!ghes_in_nmi_queue_one_entry(ghes, fixmap_idx))
                        ret = 0;
        }
        rcu_read_unlock();
@@ -919,7 +905,7 @@ int ghes_notify_sea(void)
        int rv;
 
        raw_spin_lock(&ghes_notify_lock_sea);
-       rv = ghes_in_nmi_spool_from_list(&ghes_sea);
+       rv = ghes_in_nmi_spool_from_list(&ghes_sea, FIX_APEI_GHES_NMI);
        raw_spin_unlock(&ghes_notify_lock_sea);
 
        return rv;
@@ -962,7 +948,7 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
                return ret;
 
        raw_spin_lock(&ghes_notify_lock_nmi);
-       if (!ghes_in_nmi_spool_from_list(&ghes_nmi))
+       if (!ghes_in_nmi_spool_from_list(&ghes_nmi, FIX_APEI_GHES_NMI))
                ret = NMI_HANDLED;
        raw_spin_unlock(&ghes_notify_lock_nmi);