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Date: Mon, 7 Sep 2020 15:15:36 +0200
From: Joerg Roedel <joro@...tes.org>
To: x86@...nel.org
Cc: Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Jiri Slaby <jslaby@...e.cz>,
Dan Williams <dan.j.williams@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
Juergen Gross <jgross@...e.com>,
Kees Cook <keescook@...omium.org>,
David Rientjes <rientjes@...gle.com>,
Cfir Cohen <cfir@...gle.com>,
Erdem Aktas <erdemaktas@...gle.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mike Stunes <mstunes@...are.com>,
Sean Christopherson <sean.j.christopherson@...el.com>,
Martin Radev <martin.b.radev@...il.com>,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Subject: [PATCH v7 35/72] x86/head/64: Move early exception dispatch to C code
From: Joerg Roedel <jroedel@...e.de>
Move the assembly coded dispatch between page-faults and all other
exceptions to C code to make it easier to maintain and extend.
Also change the return-type of early_make_pgtable() to bool and make it
static.
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
arch/x86/include/asm/pgtable.h | 2 +-
arch/x86/include/asm/setup.h | 4 +++-
arch/x86/kernel/head64.c | 19 +++++++++++++++----
arch/x86/kernel/head_64.S | 11 +----------
4 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5e0dcc20614d..a02c67291cfc 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -28,7 +28,7 @@
#include <asm-generic/pgtable_uffd.h>
extern pgd_t early_top_pgt[PTRS_PER_PGD];
-int __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
+bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm);
void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 4b3ca5ade2fd..7d7a064af6ff 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -39,6 +39,8 @@ void vsmp_init(void);
static inline void vsmp_init(void) { }
#endif
+struct pt_regs;
+
void setup_bios_corruption_check(void);
void early_platform_quirks(void);
@@ -49,8 +51,8 @@ extern void i386_reserve_resources(void);
extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp);
extern unsigned long __startup_secondary_64(void);
extern void startup_64_setup_env(unsigned long physbase);
-extern int early_make_pgtable(unsigned long address);
extern void early_setup_idt(void);
+extern void __init do_early_exception(struct pt_regs *regs, int trapnr);
#ifdef CONFIG_X86_INTEL_MID
extern void x86_intel_mid_early_setup(void);
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7bfd5c27c773..4282dac694c3 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -38,6 +38,8 @@
#include <asm/fixmap.h>
#include <asm/realmode.h>
#include <asm/desc.h>
+#include <asm/extable.h>
+#include <asm/trapnr.h>
/*
* Manage page tables very early on.
@@ -317,7 +319,7 @@ static void __init reset_early_page_tables(void)
}
/* Create a new PMD entry */
-int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
+bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
{
unsigned long physaddr = address - __PAGE_OFFSET;
pgdval_t pgd, *pgd_p;
@@ -327,7 +329,7 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
/* Invalid address or early pgt is done ? */
if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
- return -1;
+ return false;
again:
pgd_p = &early_top_pgt[pgd_index(address)].pgd;
@@ -384,10 +386,10 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
}
pmd_p[pmd_index(address)] = pmd;
- return 0;
+ return true;
}
-int __init early_make_pgtable(unsigned long address)
+static bool __init early_make_pgtable(unsigned long address)
{
unsigned long physaddr = address - __PAGE_OFFSET;
pmdval_t pmd;
@@ -397,6 +399,15 @@ int __init early_make_pgtable(unsigned long address)
return __early_make_pgtable(address, pmd);
}
+void __init do_early_exception(struct pt_regs *regs, int trapnr)
+{
+ if (trapnr == X86_TRAP_PF &&
+ early_make_pgtable(native_read_cr2()))
+ return;
+
+ early_fixup_exception(regs, trapnr);
+}
+
/* Don't add a printk in there. printk relies on the PDA which is not initialized
yet. */
static void __init clear_bss(void)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 1de09b58e578..3b40ec44a67d 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -341,18 +341,9 @@ SYM_CODE_START_LOCAL(early_idt_handler_common)
pushq %r15 /* pt_regs->r15 */
UNWIND_HINT_REGS
- cmpq $14,%rsi /* Page fault? */
- jnz 10f
- GET_CR2_INTO(%rdi) /* can clobber %rax if pv */
- call early_make_pgtable
- andl %eax,%eax
- jz 20f /* All good */
-
-10:
movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */
- call early_fixup_exception
+ call do_early_exception
-20:
decl early_recursion_flag(%rip)
jmp restore_regs_and_return_to_kernel
SYM_CODE_END(early_idt_handler_common)
--
2.28.0
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