From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 12 Oct 2020 22:15:24 +0000 (-0700)
Subject: Merge tag 'x86-paravirt-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: baikal/aarch64/sdk6.1~8230
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=b4145dc5d2066b0c46704e70e9c4c28a2719114b;p=kernel.git

Merge tag 'x86-paravirt-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 paravirt cleanup from Ingo Molnar:
 "Clean up the paravirt code after the removal of 32-bit Xen PV support"

* tag 'x86-paravirt-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/paravirt: Avoid needless paravirt step clearing page table entries
  x86/paravirt: Remove set_pte_at() pv-op
  x86/entry/32: Simplify CONFIG_XEN_PV build dependency
  x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT
  x86/paravirt: Clean up paravirt macros
  x86/paravirt: Remove 32-bit support from CONFIG_PARAVIRT_XXL
---

b4145dc5d2066b0c46704e70e9c4c28a2719114b
diff --cc arch/x86/kernel/kprobes/core.c
index 882b95313ad64,2ca10b770cfff..db8f8693ab8d0
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@@ -776,13 -775,115 +776,12 @@@ __used __visible void *trampoline_handl
  	/* fixup registers */
  	regs->cs = __KERNEL_CS;
  #ifdef CONFIG_X86_32
- 	regs->cs |= get_kernel_rpl();
  	regs->gs = 0;
  #endif
 -	/* We use pt_regs->sp for return address holder. */
 -	frame_pointer = &regs->sp;
 -	regs->ip = trampoline_address;
 +	regs->ip = (unsigned long)&kretprobe_trampoline;
  	regs->orig_ax = ~0UL;
  
 -	/*
 -	 * It is possible to have multiple instances associated with a given
 -	 * task either because multiple functions in the call path have
 -	 * return probes installed on them, and/or more than one
 -	 * return probe was registered for a target function.
 -	 *
 -	 * We can handle this because:
 -	 *     - instances are always pushed into the head of the list
 -	 *     - when multiple return probes are registered for the same
 -	 *	 function, the (chronologically) first instance's ret_addr
 -	 *	 will be the real return address, and all the rest will
 -	 *	 point to kretprobe_trampoline.
 -	 */
 -	hlist_for_each_entry(ri, head, hlist) {
 -		if (ri->task != current)
 -			/* another task is sharing our hash bucket */
 -			continue;
 -		/*
 -		 * Return probes must be pushed on this hash list correct
 -		 * order (same as return order) so that it can be popped
 -		 * correctly. However, if we find it is pushed it incorrect
 -		 * order, this means we find a function which should not be
 -		 * probed, because the wrong order entry is pushed on the
 -		 * path of processing other kretprobe itself.
 -		 */
 -		if (ri->fp != frame_pointer) {
 -			if (!skipped)
 -				pr_warn("kretprobe is stacked incorrectly. Trying to fixup.\n");
 -			skipped = true;
 -			continue;
 -		}
 -
 -		orig_ret_address = (unsigned long)ri->ret_addr;
 -		if (skipped)
 -			pr_warn("%ps must be blacklisted because of incorrect kretprobe order\n",
 -				ri->rp->kp.addr);
 -
 -		if (orig_ret_address != trampoline_address)
 -			/*
 -			 * This is the real return address. Any other
 -			 * instances associated with this task are for
 -			 * other calls deeper on the call stack
 -			 */
 -			break;
 -	}
 -
 -	kretprobe_assert(ri, orig_ret_address, trampoline_address);
 -
 -	correct_ret_addr = ri->ret_addr;
 -	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 -		if (ri->task != current)
 -			/* another task is sharing our hash bucket */
 -			continue;
 -		if (ri->fp != frame_pointer)
 -			continue;
 -
 -		orig_ret_address = (unsigned long)ri->ret_addr;
 -		if (ri->rp && ri->rp->handler) {
 -			__this_cpu_write(current_kprobe, &ri->rp->kp);
 -			ri->ret_addr = correct_ret_addr;
 -			ri->rp->handler(ri, regs);
 -			__this_cpu_write(current_kprobe, &kprobe_busy);
 -		}
 -
 -		recycle_rp_inst(ri, &empty_rp);
 -
 -		if (orig_ret_address != trampoline_address)
 -			/*
 -			 * This is the real return address. Any other
 -			 * instances associated with this task are for
 -			 * other calls deeper on the call stack
 -			 */
 -			break;
 -	}
 -
 -	kretprobe_hash_unlock(current, &flags);
 -
 -	kprobe_busy_end();
 -
 -	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
 -		hlist_del(&ri->hlist);
 -		kfree(ri);
 -	}
 -	return (void *)orig_ret_address;
 +	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, &regs->sp);
  }
  NOKPROBE_SYMBOL(trampoline_handler);