[CRIU] [PATCH 14/22] restorer: introduced the multiarch support into the restorer.

[Pavel Emelyanov]

On 12/27/2012 10:51 AM, Alexander Kartashov wrote:
> * Introduced the macro RT_SIGFRAME_UC to access the user context of a sigframe.
> 
> * Introduced TLS restoration for ARM.
> 
> * Don't touch a VMA that lies outside the virtual address space area 0..TASK_SIZE,
>   because VM above TASK_SIZE is read-only but some areas are mapped on ARM
>   into the process address space.
> 
> * Introduced the macro SIGFRAME_OFFSET to tune the beginning of a sigframe
>   on different architectures.
> 
> Signed-off-by: Alexander Kartashov <alekskartashov at parallels.com>
> ---
>  arch/x86/include/asm/restorer.h |    4 ++++
>  include/restorer.h              |   14 +++++++++-----
>  pie/restorer.c                  |   23 +++++++++++++++++++----
>  3 files changed, 32 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/include/asm/restorer.h b/arch/x86/include/asm/restorer.h
> index 1ccc93c..4518064 100644
> --- a/arch/x86/include/asm/restorer.h
> +++ b/arch/x86/include/asm/restorer.h
> @@ -129,9 +129,13 @@ struct rt_sigframe {
>  		     : "r"(ret)					\
>  		     : "memory")
>  
> +#define RT_SIGFRAME_UC(rt_sigframe) rt_sigframe->uc
> +
>  
>  int restore_gpregs(struct rt_sigframe *f, UserX86RegsEntry *r);
>  
>  int restore_fpu(struct rt_sigframe *sigframe, struct thread_restore_args *args);
>  
> +static void __attribute__ ((unused)) restore_tls(u32 tls) { }

Why unused?

> +
>  #endif
> diff --git a/include/restorer.h b/include/restorer.h
> index 7548ae1..3bb40b9 100644
> --- a/include/restorer.h
> +++ b/include/restorer.h
> @@ -17,10 +17,6 @@
>  #include "../protobuf/creds.pb-c.h"
>  #include "../protobuf/core.pb-c.h"
>  
> -#ifndef CONFIG_X86_64
> -# error Only x86-64 is supported
> -#endif
> -
>  struct task_restore_core_args;
>  struct thread_restore_args;
>  
> @@ -67,7 +63,10 @@ struct thread_restore_args {
>  	struct restore_mem_zone		mem_zone;
>  
>  	int				pid;
> -	UserX86RegsEntry		gpregs;
> +	UserRegsEntry		        gpregs;
> +
> +	u32				tls;
> +
>  	u64				clear_tid_addr;
>  
>  	bool				has_futex;
> @@ -126,6 +125,7 @@ struct task_restore_core_args {
>  	u64				mm_saved_auxv[AT_VECTOR_SIZE];
>  	u32				mm_saved_auxv_size;
>  	char				comm[TASK_COMM_LEN];
> +	uint32_t                        tls;

Master thread's tls should be on one of the thread_restore_args.

>  
>  	int				*rst_tcp_socks;
>  	int				rst_tcp_socks_size;
> @@ -199,4 +199,8 @@ find_shmem(struct shmems *shmems, unsigned long shmid)
>  			(vma_entry_is(vma, VMA_ANON_PRIVATE) || \
>  			vma_entry_is(vma, VMA_FILE_PRIVATE)))
>  
> +#define SIGFRAME_OFFSET 8
> +
> +#include "asm/memcpy_64.h"
> +
>  #endif /* __CR_RESTORER_H__ */
> diff --git a/pie/restorer.c b/pie/restorer.c
> index 04e7ab5..a9b4448 100644
> --- a/pie/restorer.c
> +++ b/pie/restorer.c
> @@ -156,7 +156,7 @@ static int restore_thread_common(struct rt_sigframe *sigframe,
>  	}
>  
>  	if (args->has_blk_sigset)
> -		sigframe->uc.uc_sigmask.sig[0] = args->blk_sigset;
> +		RT_SIGFRAME_UC(sigframe).uc_sigmask.sig[0] = args->blk_sigset;
>  
>  	restore_sched_info(&args->sp);
>  	if (restore_fpu(sigframe, args))
> @@ -189,6 +189,7 @@ long __export_restore_thread(struct thread_restore_args *args)
>  
>  	restore_creds(&args->ta->creds);
>  
> +	restore_tls(args->tls);
>  
>  	pr_info("%ld: Restored\n", sys_gettid());
>  
> @@ -197,7 +198,7 @@ long __export_restore_thread(struct thread_restore_args *args)
>  
>  	futex_dec_and_wake(&thread_inprogress);
>  
> -	new_sp = (long)rt_sigframe + 8;
> +	new_sp = (long)rt_sigframe + SIGFRAME_OFFSET;
>  	ARCH_RT_SIGRETURN(new_sp);
>  
>  core_restore_end:
> @@ -399,6 +400,10 @@ long __export_restore_task(struct task_restore_core_args *args)
>  			}
>  		}
>  
> +		if (vma_entry->end >= TASK_SIZE) {
> +			continue;
> +		}
> +
>  		if (vma_entry->end > premmapped_end) {
>  			if (vma_entry->start < premmapped_end)
>  				addr = premmapped_end;
> @@ -421,6 +426,10 @@ long __export_restore_task(struct task_restore_core_args *args)
>  		if (!vma_priv(vma_entry))
>  			continue;
>  
> +		if (vma_entry->end >= TASK_SIZE) {
> +			continue;
> +		}
> +
>  		if (vma_entry->start > vma_entry->shmid)
>  			break;
>  
> @@ -438,6 +447,10 @@ long __export_restore_task(struct task_restore_core_args *args)
>  		if (!vma_priv(vma_entry))
>  			continue;
>  
> +		if (vma_entry->start > TASK_SIZE) {
> +			continue;
> +		}
> +
>  		if (vma_entry->start < vma_entry->shmid)
>  			break;
>  
> @@ -684,14 +697,16 @@ long __export_restore_task(struct task_restore_core_args *args)
>  
>  	ret = sys_munmap(args->task_entries, TASK_ENTRIES_SIZE);
>  	if (ret < 0) {
> -		ret = ((long)__LINE__ << 32) | -ret;
> +		ret = ((long)__LINE__ << 16) | ((-ret) & 0xffff);

This hunk is not described in patch comment.

>  		goto core_restore_failed;
>  	}
>  
> +	restore_tls(args->tls);
> +
>  	/*
>  	 * Sigframe stack.
>  	 */
> -	new_sp = (long)rt_sigframe + 8;
> +	new_sp = (long)rt_sigframe + SIGFRAME_OFFSET;
>  
>  	/*
>  	 * Prepare the stack and call for sigreturn,
>