[tip:x86/boot] x86/boot: Use proper array element type in memset( ) size calculation

From: tip-bot for Alexander Kuleshov
Date: Tue Feb 09 2016 - 11:11:01 EST


Commit-ID: a91bbe017552b80e12d712c85549b933a62c6ed4
Gitweb: http://git.kernel.org/tip/a91bbe017552b80e12d712c85549b933a62c6ed4
Author: Alexander Kuleshov <kuleshovmail@xxxxxxxxx>
AuthorDate: Tue, 9 Feb 2016 19:44:54 +0600
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 9 Feb 2016 14:55:48 +0100

x86/boot: Use proper array element type in memset() size calculation

I changed open coded zeroing loops to explicit memset()s in the
following commit:

5e9ebbd87a99 ("x86/boot: Micro-optimize reset_early_page_tables()")

The base for the size argument of memset was sizeof(pud_p/pmd_p), which
are pointers - but the initialized array has pud_t/pmd_t elements.

Luckily the two types had the same size, so this did not result in any
runtime misbehavior.

Signed-off-by: Alexander Kuleshov <kuleshovmail@xxxxxxxxx>
Cc: Alexander Popov <alpopov@xxxxxxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1455025494-4063-1-git-send-email-kuleshovmail@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/head64.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 35843ca..7793a17 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -75,7 +75,7 @@ again:
}

pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
- memset(pud_p, 0, sizeof(pud_p) * PTRS_PER_PUD);
+ memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
*pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
}
pud_p += pud_index(address);
@@ -90,7 +90,7 @@ again:
}

pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
- memset(pmd_p, 0, sizeof(pmd_p) * PTRS_PER_PMD);
+ memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
*pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
}
pmd = (physaddr & PMD_MASK) + early_pmd_flags;