[Xen-changelog] [xen stable-4.10] xen/arm: vpsci: Remove parameter 'ver' from do_common_cpu

[patchbot@xxxxxxx]

commit 51742fbc0880432ccdea96bb3f2bf6aee2772eb8
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Fri Feb 23 18:57:24 2018 +0000
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Tue Apr 3 16:51:57 2018 -0700

    xen/arm: vpsci: Remove parameter 'ver' from do_common_cpu
    
    Currently, the behavior of do_common_cpu will slightly change depending
    on the PSCI version passed in parameter. Looking at the code, more the
    specific 0.2 behavior could move out of the function or adapted for 0.1:
    
        - x0/r0 can be updated on PSCI 0.1 because general purpose registers
        are undefined upon CPU on. This was deduced from the spec not
        mentioning the state of general purpose registers on CPU on.
        - PSCI 0.1 does not defined PSCI_ALREADY_ON. However, it would be
        safer to bail out if the CPU is already on.
    
    Based on this, the parameter 'ver' is removed and do_psci_cpu_on
    (implementation for PSCI 0.1) is adapted to avoid returning
    PSCI_ALREADY_ON.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Reviewed-by: Volodymyr Babchuk <volodymyr.babchuk@xxxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
    Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    (cherry picked from commit baba8102bfbd24f6b452342bfbe660be77300fc4)
---
 xen/arch/arm/vpsci.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/xen/arch/arm/vpsci.c b/xen/arch/arm/vpsci.c
index fdcc30454a..b4bd5a3091 100644
--- a/xen/arch/arm/vpsci.c
+++ b/xen/arch/arm/vpsci.c
@@ -23,7 +23,7 @@
 #include <public/sched.h>
 
 static int do_common_cpu_on(register_t target_cpu, register_t entry_point,
-                       register_t context_id,int ver)
+                            register_t context_id)
 {
     struct vcpu *v;
     struct domain *d = current->domain;
@@ -41,8 +41,7 @@ static int do_common_cpu_on(register_t target_cpu, register_t 
entry_point,
     if ( is_64bit_domain(d) && is_thumb )
         return PSCI_INVALID_PARAMETERS;
 
-    if ( (ver == PSCI_VERSION(0, 2)) &&
-            !test_bit(_VPF_down, &v->pause_flags) )
+    if ( !test_bit(_VPF_down, &v->pause_flags) )
         return PSCI_ALREADY_ON;
 
     if ( (ctxt = alloc_vcpu_guest_context()) == NULL )
@@ -56,18 +55,21 @@ static int do_common_cpu_on(register_t target_cpu, 
register_t entry_point,
     ctxt->ttbr0 = 0;
     ctxt->ttbr1 = 0;
     ctxt->ttbcr = 0; /* Defined Reset Value */
+
+    /*
+     * x0/r0_usr are always updated because for PSCI 0.1 the general
+     * purpose registers are undefined upon CPU_on.
+     */
     if ( is_32bit_domain(d) )
     {
         ctxt->user_regs.cpsr = PSR_GUEST32_INIT;
-        if ( ver == PSCI_VERSION(0, 2) )
-            ctxt->user_regs.r0_usr = context_id;
+        ctxt->user_regs.r0_usr = context_id;
     }
 #ifdef CONFIG_ARM_64
     else
     {
         ctxt->user_regs.cpsr = PSR_GUEST64_INIT;
-        if ( ver == PSCI_VERSION(0, 2) )
-            ctxt->user_regs.x0 = context_id;
+        ctxt->user_regs.x0 = context_id;
     }
 #endif
 
@@ -94,7 +96,14 @@ static int do_common_cpu_on(register_t target_cpu, 
register_t entry_point,
 
 static int32_t do_psci_cpu_on(uint32_t vcpuid, register_t entry_point)
 {
-    return do_common_cpu_on(vcpuid, entry_point, 0 , PSCI_VERSION(0, 1));
+    int32_t ret;
+
+    ret = do_common_cpu_on(vcpuid, entry_point, 0);
+    /*
+     * PSCI 0.1 does not define the return code PSCI_ALREADY_ON.
+     * Instead, return PSCI_INVALID_PARAMETERS.
+     */
+    return (ret == PSCI_ALREADY_ON) ? PSCI_INVALID_PARAMETERS : ret;
 }
 
 static int32_t do_psci_cpu_off(uint32_t power_state)
@@ -138,8 +147,7 @@ static int32_t do_psci_0_2_cpu_on(register_t target_cpu,
                                   register_t entry_point,
                                   register_t context_id)
 {
-    return do_common_cpu_on(target_cpu, entry_point, context_id,
-                            PSCI_VERSION(0, 2));
+    return do_common_cpu_on(target_cpu, entry_point, context_id);
 }
 
 static const unsigned long target_affinity_mask[] = {
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.10

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