[PATCH v4 06/48] target/microblaze: Do not set MO_ALIGN for user-only

Richard Henderson posted 48 patches 1 month, 2 weeks ago
Maintainers: Yoshinori Sato <ysato@users.sourceforge.jp>, Aurelien Jarno <aurelien@aurel32.net>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Richard Henderson <richard.henderson@linaro.org>, Alistair Francis <Alistair.Francis@wdc.com>, Cornelia Huck <cohuck@redhat.com>, Laurent Vivier <laurent@vivier.eu>, Paolo Bonzini <pbonzini@redhat.com>, Jiaxun Yang <jiaxun.yang@flygoat.com>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Stefan Weil <sw@weilnetz.de>, Greg Kurz <groug@kaod.org>, Eduardo Habkost <ehabkost@redhat.com>, David Gibson <david@gibson.dropbear.id.au>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Riku Voipio <riku.voipio@iki.fi>, "Alex Bennée" <alex.bennee@linaro.org>, Artyom Tarasenko <atar4qemu@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Taylor Simpson <tsimpson@quicinc.com>, Peter Maydell <peter.maydell@linaro.org>, David Hildenbrand <david@redhat.com>, Thomas Huth <thuth@redhat.com>

[PATCH v4 06/48] target/microblaze: Do not set MO_ALIGN for user-only

Posted by Richard Henderson 1 month, 2 weeks ago
The kernel will fix up unaligned accesses, so emulate that
by allowing unaligned accesses to succeed.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/microblaze/translate.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/target/microblaze/translate.c b/target/microblaze/translate.c
index a14ffed784..ef44bca2fd 100644
--- a/target/microblaze/translate.c
+++ b/target/microblaze/translate.c
@@ -727,6 +727,7 @@ static TCGv compute_ldst_addr_ea(DisasContext *dc, int ra, int rb)
 }
 #endif
 
+#ifndef CONFIG_USER_ONLY
 static void record_unaligned_ess(DisasContext *dc, int rd,
                                  MemOp size, bool store)
 {
@@ -739,6 +740,7 @@ static void record_unaligned_ess(DisasContext *dc, int rd,
 
     tcg_set_insn_start_param(dc->insn_start, 1, iflags);
 }
+#endif
 
 static bool do_load(DisasContext *dc, int rd, TCGv addr, MemOp mop,
                     int mem_index, bool rev)
@@ -760,12 +762,19 @@ static bool do_load(DisasContext *dc, int rd, TCGv addr, MemOp mop,
         }
     }
 
+    /*
+     * For system mode, enforce alignment if the cpu configuration
+     * requires it.  For user-mode, the Linux kernel will have fixed up
+     * any unaligned access, so emulate that by *not* setting MO_ALIGN.
+     */
+#ifndef CONFIG_USER_ONLY
     if (size > MO_8 &&
         (dc->tb_flags & MSR_EE) &&
         dc->cfg->unaligned_exceptions) {
         record_unaligned_ess(dc, rd, size, false);
         mop |= MO_ALIGN;
     }
+#endif
 
     tcg_gen_qemu_ld_i32(reg_for_write(dc, rd), addr, mem_index, mop);
 
@@ -906,12 +915,19 @@ static bool do_store(DisasContext *dc, int rd, TCGv addr, MemOp mop,
         }
     }
 
+    /*
+     * For system mode, enforce alignment if the cpu configuration
+     * requires it.  For user-mode, the Linux kernel will have fixed up
+     * any unaligned access, so emulate that by *not* setting MO_ALIGN.
+     */
+#ifndef CONFIG_USER_ONLY
     if (size > MO_8 &&
         (dc->tb_flags & MSR_EE) &&
         dc->cfg->unaligned_exceptions) {
         record_unaligned_ess(dc, rd, size, true);
         mop |= MO_ALIGN;
     }
+#endif
 
     tcg_gen_qemu_st_i32(reg_for_read(dc, rd), addr, mem_index, mop);
 
-- 
2.25.1