From: Juergen Gross jgross@suse.com
commit 96e8fc5818686d4a1591bb6907e7fdb64ef29884 upstream.
Instead of clearing the bss area in assembly code, use the clear_bss() function.
This requires to pass the start_info address as parameter to xen_start_kernel() in order to avoid the xen_start_info being zeroed again.
Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Jan Beulich jbeulich@suse.com Reviewed-by: Boris Ostrovsky boris.ostrovsky@oracle.com Link: https://lore.kernel.org/r/20220630071441.28576-2-jgross@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/setup.h | 3 +++ arch/x86/kernel/head64.c | 2 +- arch/x86/xen/enlighten_pv.c | 8 ++++++-- arch/x86/xen/xen-head.S | 10 +--------- 4 files changed, 11 insertions(+), 12 deletions(-)
--- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -132,6 +132,9 @@ void *extend_brk(size_t size, size_t ali }
extern void probe_roms(void); + +void clear_bss(void); + #ifdef __i386__
asmlinkage void __init i386_start_kernel(void); --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -421,7 +421,7 @@ void __init do_early_exception(struct pt
/* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ -static void __init clear_bss(void) +void __init clear_bss(void) { memset(__bss_start, 0, (unsigned long) __bss_stop - (unsigned long) __bss_start); --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1183,15 +1183,19 @@ static void __init xen_domu_set_legacy_f extern void early_xen_iret_patch(void);
/* First C function to be called on Xen boot */ -asmlinkage __visible void __init xen_start_kernel(void) +asmlinkage __visible void __init xen_start_kernel(struct start_info *si) { struct physdev_set_iopl set_iopl; unsigned long initrd_start = 0; int rc;
- if (!xen_start_info) + if (!si) return;
+ clear_bss(); + + xen_start_info = si; + __text_gen_insn(&early_xen_iret_patch, JMP32_INSN_OPCODE, &early_xen_iret_patch, &xen_iret, JMP32_INSN_SIZE); --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -48,15 +48,6 @@ SYM_CODE_START(startup_xen) ANNOTATE_NOENDBR cld
- /* Clear .bss */ - xor %eax,%eax - mov $__bss_start, %rdi - mov $__bss_stop, %rcx - sub %rdi, %rcx - shr $3, %rcx - rep stosq - - mov %rsi, xen_start_info mov initial_stack(%rip), %rsp
/* Set up %gs. @@ -71,6 +62,7 @@ SYM_CODE_START(startup_xen) cdq wrmsr
+ mov %rsi, %rdi call xen_start_kernel SYM_CODE_END(startup_xen) __FINIT