From f520e55241e1cf0c10d308ccf47513f28533f60a Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@gmx.de>
Date: Tue, 25 Jul 2017 18:20:54 +0200
Subject: [PATCH] parisc: Fix crash when calling PDC_PAT_MEM PDT firmware
function
Commit c9c2877d08d9 ("parisc: Add Page Deallocation Table (PDT) support")
introduced the pdc_pat_mem_read_pd_pdt() firmware helper function, which
crashed the system because it trashed the stack if the
pdc_pat_mem_read_pd_retinfo struct was located on the stack (and which is
in size less than the required 32 64-bit values).
Fix it by using the pdc_result struct instead when calling firmware and copy
the return values back into the result struct when finished sucessfully.
While debugging this code I noticed that the pdc_type wasn't set correctly
either, so let's fix that too.
Fixes: c9c2877d08d9 ("parisc: Add Page Deallocation Table (PDT) support")
Signed-off-by: Helge Deller <deller@gmx.de>
---
arch/parisc/kernel/firmware.c | 11 +++++++++--
arch/parisc/kernel/pdt.c | 4 +++-
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/parisc/kernel/firmware.c b/arch/parisc/kernel/firmware.c
index 98190252c12f..526ed90ca56f 100644
--- a/arch/parisc/kernel/firmware.c
+++ b/arch/parisc/kernel/firmware.c
@@ -1481,12 +1481,19 @@ int pdc_pat_mem_read_pd_pdt(struct pdc_pat_mem_read_pd_retinfo *pret,
unsigned long offset)
{
int retval;
- unsigned long flags;
+ unsigned long flags, entries;
spin_lock_irqsave(&pdc_lock, flags);
retval = mem_pdc_call(PDC_PAT_MEM, PDC_PAT_MEM_PD_READ,
- __pa(&pret), __pa(pdt_entries_ptr),
+ __pa(&pdc_result), __pa(pdt_entries_ptr),
count, offset);
+
+ if (retval == PDC_OK) {
+ entries = min(pdc_result[0], count);
+ pret->actual_count_bytes = entries;
+ pret->pdt_entries = entries / sizeof(unsigned long);
+ }
+
spin_unlock_irqrestore(&pdc_lock, flags);
return retval;
diff --git a/arch/parisc/kernel/pdt.c b/arch/parisc/kernel/pdt.c
index f3a797e670b0..040d49b723d7 100644
--- a/arch/parisc/kernel/pdt.c
+++ b/arch/parisc/kernel/pdt.c
@@ -112,10 +112,12 @@ void __init pdc_pdt_init(void)
#ifdef CONFIG_64BIT
struct pdc_pat_mem_read_pd_retinfo pat_pret;
+ /* try old obsolete PAT firmware function first */
+ pdt_type = PDT_PAT_OLD;
ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
MAX_PDT_ENTRIES);
if (ret != PDC_OK) {
- pdt_type = PDT_PAT_OLD;
+ pdt_type = PDT_PAT_NEW;
ret = pdc_pat_mem_read_pd_pdt(&pat_pret, pdt_entry,
MAX_PDT_TABLE_SIZE, 0);
}