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ACPI / APEI: Let the notification helper specify the fixmap slot
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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 <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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@rafaeljw
James Morse authored and rafaeljw committed Feb 7, 2019
1 parent 3b880cb commit b484079
Showing 1 changed file with 39 additions and 53 deletions.
92 changes: 39 additions & 53 deletions drivers/acpi/apei/ghes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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)
Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -361,15 +342,17 @@ static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr)
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;

if (!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,
Expand Down Expand Up @@ -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)
Expand All @@ -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)) {
Expand All @@ -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;
}
Expand Down Expand Up @@ -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();
Expand All @@ -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;
Expand Down Expand Up @@ -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);

Expand Down

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