From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50145) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2fv6-00007T-Ad for qemu-devel@nongnu.org; Tue, 17 May 2016 10:24:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2fv4-0000SI-4s for qemu-devel@nongnu.org; Tue, 17 May 2016 10:24:23 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:57141) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2fv3-0000Rs-UC for qemu-devel@nongnu.org; Tue, 17 May 2016 10:24:22 -0400 From: Peter Maydell Date: Tue, 17 May 2016 15:18:02 +0100 Message-Id: <1463494687-25947-2-git-send-email-peter.maydell@linaro.org> In-Reply-To: <1463494687-25947-1-git-send-email-peter.maydell@linaro.org> References: <1463494687-25947-1-git-send-email-peter.maydell@linaro.org> Subject: [Qemu-devel] [PATCH v2 1/6] translate-all.c: Don't pass puc, locked to tb_invalidate_phys_page() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: patches@linaro.org, Paolo Bonzini , Riku Voipio , Richard Henderson , Eduardo Habkost , Sergey Fedorov The user-mode-only function tb_invalidate_phys_page() is only called from two places: * page_unprotect(), which passes in a non-zero pc, a puc pointer and the value 'true' for the locked argument * page_set_flags(), which passes in a zero pc, a NULL puc pointer and a 'false' locked argument If the pc is non-zero then we may call cpu_resume_from_signal(), which does a longjmp out of the calling code (and out of the signal handler); this is to cover the case of a target CPU with "precise self-modifying code" (currently only x86) executing a store instruction which modifies code in the same TB as the store itself. Rather than doing the longjump directly here, return a flag to the caller which indicates whether the current TB was modified, and move the longjump to page_unprotect. Signed-off-by: Peter Maydell Reviewed-by: Sergey Fedorov --- translate-all.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/translate-all.c b/translate-all.c index b54f472..4820d2e 100644 --- a/translate-all.c +++ b/translate-all.c @@ -1438,10 +1438,13 @@ void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len) } } #else -/* Called with mmap_lock held. */ -static void tb_invalidate_phys_page(tb_page_addr_t addr, - uintptr_t pc, void *puc, - bool locked) +/* Called with mmap_lock held. If pc is not 0 then it indicates the + * host PC of the faulting store instruction that caused this invalidate. + * Returns true if the caller needs to abort execution of the current + * TB (because it was modified by this store and the guest CPU has + * precise-SMC semantics). + */ +static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc) { TranslationBlock *tb; PageDesc *p; @@ -1459,7 +1462,7 @@ static void tb_invalidate_phys_page(tb_page_addr_t addr, addr &= TARGET_PAGE_MASK; p = page_find(addr >> TARGET_PAGE_BITS); if (!p) { - return; + return false; } tb = p->first_tb; #ifdef TARGET_HAS_PRECISE_SMC @@ -1498,12 +1501,10 @@ static void tb_invalidate_phys_page(tb_page_addr_t addr, modifying the memory. It will ensure that it cannot modify itself */ tb_gen_code(cpu, current_pc, current_cs_base, current_flags, 1); - if (locked) { - mmap_unlock(); - } - cpu_resume_from_signal(cpu, puc); + return true; } #endif + return false; } #endif @@ -1902,7 +1903,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags) if (!(p->flags & PAGE_WRITE) && (flags & PAGE_WRITE) && p->first_tb) { - tb_invalidate_phys_page(addr, 0, NULL, false); + tb_invalidate_phys_page(addr, 0); } p->flags = flags; } @@ -1996,7 +1997,10 @@ int page_unprotect(target_ulong address, uintptr_t pc, void *puc) /* and since the content will be modified, we must invalidate the corresponding translated code. */ - tb_invalidate_phys_page(addr, pc, puc, true); + if (tb_invalidate_phys_page(addr, pc)) { + mmap_unlock(); + cpu_resume_from_signal(current_cpu, puc); + } #ifdef DEBUG_TB_CHECK tb_invalidate_check(addr); #endif -- 1.9.1